Where are you seeing the "XML Schema has failed" message? It's not part of either the Harvester 1.x or the Harvester 2.x.
Which version are you using? I can suggest modifications to add support for additional DC fields, but be warned that either will require some PHP experience.
Finally, what sort of timeout are you seeing? There are several timeouts set in the php.ini file that might be affecting you; alternately, it might be in the code.
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