Is it a bug of SQL Server 2000 SP4?

Database backup file: 
http://www.keepmyfile.com/download/c58b2a565144

Environment:
SQL Server 2000 SP4

Problem:
The following two statements returns different number of records:
Exec GenPeriodical1 102, null, '20050601', '20050630', null, null, 0 

SELECT *
FROM dbo.OtherFee (null, '20050601', '20050630', null, null, 0)
WHERE flow_id = 102

This problem wasn't found in SQL Server 2000 original version and SQL Server 
2005.
Any help is appreciated!

Is it possible to see text for dbo.OtherFee and GenPeriodical1?|||

Thanks for your reply!

I've got the answer from the newsgroup. The replyer said it seems a bug of SP4 and gave a work-around. If you are interested in this issue, you can download the backup file, it's just 1.18MB.

The store proc and function call other functions, thus not convenient to paste them here.