As a Technical Support Consultant for CCH I would be happy to assist you further, if you are still experiencing issues please contact us on 1300 300 224 if within Australia, (otherwise internationally either via your local CCH support hotline or +61 9857 1300 within business hours Australian Eastern Standard time to contact the Aust. Support team specifically) or email [email protected] (or alternatively for EZproxy specific support contact OCLC)
To my knowledge though OCLC's EZproxy software does not block the download of data where the URL happens to use a ".rpc" extension – however it is possible (but unlikely) that a firewall/security-suite on the client-side could be configured to do this.
To troubleshoot you can use HTTP logging software to examine the HTTP request and response pairs. For Internet Explorer Microsoft's free "Fiddler" tool can be used. See: http://www.fiddler2.com
Nat