In this form I am working on, I have two fields: [Country] (which is a drop
down combo box) and [Other country], a text field which will require input if
the country of choice is not available for the user.

For example, if the user chooses "other" from the drop down list of
[country], they will need to specify the country name in the [other country]
text field. I tried to use the following formula in the validation tab:

([country] "other") OR ([other country] "")

but I got an "error in validation text formula for 'other country' --
illegal right operand for IN".
What did i do wrong? I hope someone can help me out so I can stop banging my
head against the wall. Thanks