Help! Too many items in profile field- SQL issue

This is an issue that stopped my development in 6.0, and now looks like it is a problem in 6.1 as well.

I have an international business site and I need a field in the profiles where members can select multiple countries where they want to do business.   I tried linking this to the predefined values table "country" in the profile fields builder but when I do, I get this database error:

Mysql error:
Too many strings for column Countries and SET

I then tried to sneak this in by making a new predefined table called "countries" and adding the countries one by one- but after a certain number - I think around 80, I get the exact same thing. 

Does anyone know any way around this?  i.e. is there some SQL setting I could change?  I really, really need this so any help would be appreciated.

Thanks

Rob