While I agree there is a parsing problem in there somewhere, if your filter
is just plain SQL then you should simple use the OnPrepareSQL event and the
SQLWhereItems. This is the IBO way of doing things.

Also, you can preface your filter with the prefix ::SQL:: and then
everything after that will be treated as raw SQL. Otherwise, IBO has to
parse out and make sense of your filter string and that can be rather
complex.

FWIW,
Jason Wharton
CPS - Mesa AZ
http://www.ibobjects.com