I develop against MS SQL Server 2000 db's all the time.
My company has a whole bunch of legacy db's that are SQL Server 2000
db's. So far, I have not had a problem with the SQL Server AR
adapter, with FreeTDS, in ODBC mode with Rails 2.x.
But, then again, we don't do database session store. We use the Rails
2.x default cookie based session store. So, you may have uncovered a
bug. However, that seems unlikely. The SQL Server AR adapter was
around before Rails 2.x. And, prior to Rails 2.x, I was using db
The problems I do run into are not really with AR or SQL Server. But,
rather, I have to deal with a lot of legacy/non-Rails-esque database
designs. Things like non-surrogate PK's, composite PK's, weird FK
relationships, using PK's that contain periods and "@'s" . . . just
about every weird thing you can think of . . . I've come across.
The good thing is that so far, I have been able find workarounds for
all these situations.
If you can be a little bit more specific with you problem, maybe post
some error messages or something, I would be happy to help you out.