Trying join MSSQL table with Paradox table

hello all!

I'm trying to use a TQUERY to retrive a result set with one or more
paradox tables and mssql...
my code is very simple:

select * from ":Sql_alias:dbo.customer" c, ":Paradox_alias:invoice" i
where i.codcustomer = c.codid

in the Database Desktop, this code return a "Unexpected: General
Protection Violation", in Delphi occurs a GPF.

what is going on?? How can I join a paradox with mssql???

... using delphi 2 with ms sql 6.5 and BDE 3.5

Thanx
Feijo