Error Code -1003 help please

[Thack]

Hi,

I am using Cognos 7.4 Administrator and have come to run a macro today that worked last week, but today I get the message:
Error code: - 1003
"ERROR exception not handled by program"

I've checked the things suggested when you google the error and I don't have another version of Cognos installed nor do I seem to have any .exe files hanging.

Can anyone shed some light on why this happens and how to fix it?

Thanks