Error while executing Transaction Activity

I posted the below post in the Process Flow forum but I am also posting here because I am not convinced this is entirely a Process Flow problem. Any ideas you have are appreciated. Cheers Mates.

Hello,
We are receiving the below error message from flows. This doesn't occur for all flow so it is making it very difficult to trouble shoot. Any ideas what could be causing the problem, or a method to determine the problem. I have checked the security logs, ios.log, and SystemOut.log. None of them have any information leading to the cause of the problem. If I rerun the work unit manually it completes just fine. Any help you can offer would be appreciated.

Thanks.

ErrorLog in Process : CERNERREQ_V08 Workunit : 9681, ActivityType=AGS, ActivityName=Approve, ActivityId=AGS4 Date:05/28/2010 Time:08:05:09
Error while executing Transaction Activity .....java.lang.Exception: Error connecting to http://lwsprod.ad.mhsil.com/servlet/Router/Tran
saction/Erp?_PDL=PROD&_TKN=RQ13.1&_EVT=CHG&_RTN=DATA&_LFN=TRUE&_TDS=IGNORE&FC=Approve&RQH-COMPANY=0100&RQH-REQ-NUMBER=0137424&_DELIM=%09&_O
UT=TEXT&_EOT=TRUE with user pfadmin Query string
at com.lawson.bpm.coreutils.CGIInvoker.invoke(Unknown Source)
at com.lawson.bpm.coreutils.CGIInvoker.invoke(Unknown Source)
at com.lawson.bpm.coreutils.CGIInvoker.invoke(Unknown Source)
at com.lawson.bpm.database.transaction.Transaction.doQuery(Unknown Source)
at com.lawson.bpm.database.transaction.Transaction.doQuery(Unknown Source)
at com.lawson.bpm.processflow.workFlow.flowGraph.FgaAgs.startActivity(Unknown Source)
at com.lawson.bpm.processflow.workFlow.flowGraph.FgActivity.execute(Unknown Source)
at com.lawson.bpm.processflow.workFlow.flowGraph.FgProcess.run(Unknown Source)
at com.lawson.bpm.pfengine.ProcessFlowEngine.execute(Unknown Source)
at com.lawson.bpm.pfengine.ProcessFlowEngine.startProcessAt(Unknown Source)
at com.lawson.bpm.eprocessserver.KBConnection.startProcess(Unknown Source)
at com.lawson.bpm.eprocessserver.KBConnection.startProcess(Unknown Source)
at com.lawson.bpm.eprocessserver.KBConnection.execute(Unknown Source)
at com.lawson.bpm.eprocessserver.KBConnection.run(Unknown Source)
at com.lawson.bpm.eprocessserver.util.ThreadPool$PooledThread.run(Unknown Source)