Issue with Groovy Rule

Summary:

The requirement is to transfer the data from one department to another and if in the target department entered headcount is more than available headcount in source department then the form should not allow SAVE.

Have written the groovy script and attached it to the form "Run before save". while saving the form it is giving me the below error :

"A method called by the script failed on line: 1, with error: An error occurred while processing this page."

Kindly help to resolve this issue.

Thanks in advance.

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