I am getting the errors normally associated with using undimensioned
variables in an Option Explicit module. But I haven't set Option
Explicit on that module nor anywhere else in my project (an Excel 2K3
workbook with some VBA routines).

If I dim the variables, the problem goes away.

So, I can work with it, but the problem is contrary to my understanding
of "Option Explicit".

My understanding is that "Option Explicit" only operates at module
level (says so in the Help file), but this I haven't done.

***Is it possible for a third party addin to somehow set "Option
Explicit" at the application level?

The reason I ask is that the only machine out of 11 which has the
problem is one which has a third party add-in installed. Some of the
add-in code is exposed and uses "Option Explicit", though, as expected,
on a per-module basis. Perhaps there is some code for the add-in that
I can't see.

***More generally, how can "Option Explicit" type dimensioning
requirements come to be in my module without my having set them?