Problems with process instantiation via Rest API

I am dealing with some problems using the REST API for a process instantiation.

I have a very simple process (start → step1 ->end) without contracts. The process definition ID is 7710269580874956548.

Connecting using the walter.bates user and posting /API/bpm/process/ with payload

{
    "processDefinitionId": "7710269580874956548"
}

I get the following 500 error:

{
    "exception": "class java.lang.NullPointerException",
    "message": "",
    "stacktrace": [
        "org.bonitasoft.console.common.server.utils.BonitaHomeFolderAccessor.getCompleteTempFilePath(BonitaHomeFolderAccessor.java:32)",
        "org.bonitasoft.console.common.server.utils.BonitaHomeFolderAccessor.getTempFile(BonitaHomeFolderAccessor.java:21)",
        "org.bonitasoft.web.rest.server.datastore.bpm.process.ProcessDatastore.add(ProcessDatastore.java:96)",
        "org.bonitasoft.web.rest.server.api.bpm.process.APIProcess.add(APIProcess.java:85)",
        "org.bonitasoft.web.rest.server.api.bpm.process.APIProcess.add(APIProcess.java:51)",
        "org.bonitasoft.web.rest.server.framework.API.runAdd(API.java:156)",
        "org.bonitasoft.web.rest.server.framework.APIServletCall.doPost(APIServletCall.java:213)",
        "org.bonitasoft.web.toolkit.server.servlet.ToolkitHttpServlet.doPost(ToolkitHttpServlet.java:188)",
        "javax.servlet.http.HttpServlet.service(HttpServlet.java:650)",
        "org.bonitasoft.web.toolkit.server.servlet.ToolkitHttpServlet.service(ToolkitHttpServlet.java:75)",
        "javax.servlet.http.HttpServlet.service(HttpServlet.java:731)",
        "org.bonitasoft.web.toolkit.server.servlet.ToolkitHttpServlet.service(ToolkitHttpServlet.java:226)",
        "org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)",
        "org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)",
        "org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)",
        "org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)",
        "org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)",
        "org.tuckey.web.filters.urlrewrite.RuleChain.handleRewrite(RuleChain.java:176)",
        "org.tuckey.web.filters.urlrewrite.RuleChain.doRules(RuleChain.java:145)",
        "org.tuckey.web.filters.urlrewrite.UrlRewriter.processRequest(UrlRewriter.java:92)",
        "org.tuckey.web.filters.urlrewrite.UrlRewriteFilter.doFilter(UrlRewriteFilter.java:394)",
        "org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)",
        "org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)",
        "org.bonitasoft.console.common.server.login.filter.AbstractAuthorizationFilter.doFilter(AbstractAuthorizationFilter.java:60)",
        "org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)",
        "org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)",
        "org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:747)",
        "org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:485)",
        "org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:410)",
        "org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:337)",
        "org.tuckey.web.filters.urlrewrite.NormalRewrittenUrl.doRewrite(NormalRewrittenUrl.java:213)",
        "org.tuckey.web.filters.urlrewrite.RuleChain.handleRewrite(RuleChain.java:171)",
        "org.tuckey.web.filters.urlrewrite.RuleChain.doRules(RuleChain.java:145)",
        "org.tuckey.web.filters.urlrewrite.UrlRewriter.processRequest(UrlRewriter.java:92)",
        "org.tuckey.web.filters.urlrewrite.UrlRewriteFilter.doFilter(UrlRewriteFilter.java:394)",
        "org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)",
        "org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)",
        "org.bonitasoft.console.common.server.login.filter.AbstractAuthorizationFilter.doFilter(AbstractAuthorizationFilter.java:60)",
        "org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)",
        "org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)",
        "org.bonitasoft.console.common.server.login.filter.AbstractAuthorizationFilter.doFilter(AbstractAuthorizationFilter.java:60)",
        "org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)",
        "org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)",
        "org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)",
        "org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)",
        "org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:505)",
        "org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:169)",
        "org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)",
        "org.bonitasoft.console.security.SessionFixationValve.invoke(SessionFixationValve.java:77)",
        "org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)",
        "org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:423)",
        "org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1079)",
        "org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:625)",
        "org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:318)",
        "java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)",
        "java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)",
        "org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)",
        "java.lang.Thread.run(Unknown Source)"
    ]
}

My fault. I was using the wrong service. The correct is /API/bpm/case/.

My fault. I was using the wrong service. The correct is /API/bpm/case/.