Does anyone know what caused error -904, "unavilable datbase" error?

I can connect to the embedded database file D:\Databasess\Test.fdb" on
a stand alone application, but when I cut-and-paste the code into a
DLL such that the DLL will connect to the file database upon first
function call
if (m_pDb == NULL)
....

I used the isc_expand_dpb() api to define the userId and password,

then I use isc_attach_database to attach to the database, there is
where I got the -904 error, which is "unavailable database?

What did I do wront, since my Test.exe works fine using the database file?

Thanks for any pointers in resolving this!

jml