RPC call failure , http500

HI

 

I am using LR9.52, IE8 on a windows XP machine. i am scripting a webapplication, https.

I record a script where I log into our customer site(utility company) and ask for the customers personal data. This is done by firing a couple of RPC calls. These calls get an HTTP 500 error when i play them back...please advise anybody???