This gateway is sponsored by the Deutsche Zentralbibliothek für Wirtschaftswissenschaften (ZBW) - Leibniz-Informationszentrum Wirtschaft. The gateway is maintained by me, Thomas Krichel. I recommend you use the AMF metadata format to get the most information out of the OAI and RePEc.
The easiest way to get to this data is to mirror it from ftp://oai.repec.org. When using this approach, ignore directories named '.oai', these contain material that is used to maintain the gateway.
If you insist on using OAI-PMH, you can use OAIrepecSeries.pl first drafted by me and then improved by Christopher F. Baum.
If you have questions about this gateway, please contact me at krichel at openlib dot org, with the subject line "RePEc OAI gateway".
Good luck.