What string value does:
return on the workstation(s) where this doesn’t work? (I see from your example that you check for version 6.5.2 twice – that might be a typo).
If the applet is running, then the problem most likely lies in the line where you check the version of the client. I would suggest you insert a MsgBox to see what value the version check is returning on the offending clients.
Please let me know how you proceed.