Searching for all hiddenUserTasks for a particular user

I am trying to display all hidden tasks using the REST API. I have tried the following including adding an ordering column but it is not working and I am getting exceptions.

Remote Address:127.0.0.1:8084
Request URL:http://localhost:8084/bonita/API/bpm/hiddenUserTask?p=0&f=user_id%2B203
Request Method:GET
Status Code:500 Internal Server Error
Request Headersview source
Accept:*/*
Accept-Encoding:gzip, deflate, sdch
Accept-Language:en-GB,en-US;q=0.8,en;q=0.6
Cache-Control:no-cache
Connection:keep-alive
Cookie:JSESSIONID=DE5DF1A58C1D4BB3C1E429907C19FD3C; BOS_Locale=en
Host:localhost:8084
Origin:http://localhost:4200
Pragma:no-cache
Referer:http://localhost:4200/bonita
User-Agent:Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/39.0.2171.65 Safari/537.36
Query String Parametersview sourceview URL encoded
p:0
f:user_id+203
Response Headersview source
Access-Control-Allow-Credentials:true
Access-Control-Allow-Origin:http://localhost:4200
Cache-Control:no-cache,no-store,no-transform,max-age=0
Connection:close
Content-Type:application/json;charset=UTF-8
Date:Wed, 10 Dec 2014 23:54:33 GMT
Expires:09 Dec 2014 23:54:33 GMT
Pragma:No-cache
Server:Apache-Coyote/1.1
Transfer-Encoding:chunked
Vary:Origin

Hello,
you need to filter on hidded_user_id with your user’s id, something like GET:

http://localhost:8080/bonita/API/bpm/humanTask?p=0&c=10&f=hidden_user_id%3D4