Thanks for the suggestions, Ties Blom. I am loading the data into Oracle, but we will soon be switching from oracle to DB2 on AIX. Does DTS only work with SQL Server? The main problem I found with the ETL tools that I tested is that they tried to load the data into are target database using inserts and updates instead of using oracle's native sql-loader utility. My benchmark tests showed the SQL-Loader to be approximately 30 times faster than loading the data with inserts and updates.
As for Access quirks, I did run into locking issues because I was running 3 instances of the access database in parallel. I solved this problem by creating a cmd file that makes three separate copies of the mdb and executes those 3 copies in parallel. Since I did that, the locking issues vanished. The strange part is that I'm only doing selects, no updates or inserts, so I don't know why I would have had locking issues.