Question:
What does a return code of 100 mean on a START REPORT statement?

Answer:
If this is an Informix error, and it probably is, Informix lists the following error message:

-100ISAM error: duplicate value for a record with unique key.

A row that was to be inserted or updated has a key value that already exists in its index. For C-ISAM programs, a duplicate value was presented in the last call to iswrite, isrewrite, isrewcurr, or isaddindex. Review the program logic and the input data. For SQL products, a duplicate key value was used in the last INSERT or UPDATE.

It looks like you are not connecting properly to the database and are getting no data returned.