It looks like a variable containing the string ‘Token failed execution’ was passed to a subroutine that expects an integer. But I don’t see a place in your quoted code line where such a variable is being used. I think the error is associated with a different line of code. The most likely reason is that an ‘on error’ statement is suppressing normal error-handling. This implies there is an unhandled error, that occurs earlier in the code execution.
Does this problem appear for all users of your applet or only these two? Perhaps there is something common to the two users’ environments that leads to this issue. It may be due to the version of Formativ or GroupWise, or something else. I suggest you review their Formativ configurations, which can be obtained from the GroupWise client Help menu: select About Formativ, then go to the Configuration tab.