Login Problems

I'm having problems connecting to an informix database using a GUI program in windows. The error i keep getting is "database not found or no system permissions", but the database is there exactly how I've written it and I have permissions to log into the database. I've logged into the database via telnet and run a few queries. To make things even more interesting some of my users can log in, and some can't. It doesn't seem to make a difference what level of access they have. I have a DBA that can't login, but user with only select permissions who can. I'm using the Informix Standard Engine on a Linux server. The program i'm trying to connect with was written with Delphi 5 and uses BDE version 5.1. Does anyone know what processes a login goes through while it is in the process of logging in? Is there a logfile or system utility that would allow me to track exactly what is happening when I'm attempting to log in?