I did a quick test using a VSM in ITR with the above script, copied an pasted as-is, nothing changed:
I fired the following url at the waiting VSM http://localhost:8002/someContext?operationName/0/1/2/3/4/5/6/7/8/9/10/11/12/13/14
And below you can see the first bold line, that is the request after the HTTP TPH with only one argument (it is a JSON representation of the request as logged in the workstation system messages)
And the second bold line is the request transformed buy the Scriptable DPH now with the original argument removed and replaced by 15 "splitted" arguments.
INFO - Name: GetUrlArgument Version: -1 created with LISA 10.3.0 (10.3.0.297)
INFO - Test Case Saved to: C:\CA\CDBOK\JSON_Processing\Tests\GetUrlArgument.tst
INFO - Test Case Results Saved to: C:\CA\CDBOK\JSON_Processing\Tests\GetUrlArgument.rsp
INFO - Name: ParseUrlArgument Version: 5 created with LISA 10.3.0 (10.3.0.297)
INFO - Inbound Request {"id":0,"operation":"POST /someContext","arguments":{"operationName/0/1/2/3/4/5/6/7/8/9/10/11/12/13/14":"operationName/0/1/2/3/4/5/6/7/8/9/10/11/12/13/14"}}
INFO - Inbound Request {"id":0,"operation":"POST /someContext","arguments":{"operationName":"operationName","version":"0","appName":"1","appDevice":"2","tokenID":"3","refID":"4","participantID":"5","check1":"6","embedURL":"7","fromDate":"8","toDate":"9","check2":"10","someID":"11","clientID":"12","embedOpName":"13","check3":"14"}}
INFO - (setSelectedNode) index: 0
So, as thescript seems to function fine, I think the error is in the request that you fire at the virtual service, can you post the url that fails on your side? Also, please post the complete script error message.
Cheers,
Danny