I was deploying GP SSRS Reports on SQL Server 2008 64 Bit and was facing the following error message:

There was an exception running the extensions specified in the config file. —> Maximum request length exceeded.

Googled it and here the resolution: http://www.developmentnow.com/g/115_2006_4_0_0_735861/Request-Length-Exceeded.htm

I hope this would be a useful tip for people out there deploying SSRS for GP.

VAIDY