Which EPiServer version? You posted both in 6 R2 and 6 R1.
There are some known bugs in the compare version, some which are fixed in R2.
Do you have a custom property defined on those pages?
No, its a fairly basic page with only 4 properties of types XHTML String, Page, Integer and String <= 255.
I think the issue is with the amount of content in the XHTML field as it's fine with not much content but when comparing 2 versions that have a lot of content I get the issue (I think it's too much for the request).
I have an interesting situation when comparing versions of a page where the versions being compared both have a large amount of content in a field of type XHTML > 255. Using compare on the versions hangs for ages then returns a connection error with nothing being added to the event log.
On investigtion and using Fiddler I found that the error "ReadResponse() failed: The server did not return a response for this request" was being returned which in turn led me to add tracing to my application (courtesy of http://www.peter-urda.com/2010/09/follow-up-iis-services-504s-and-fiddler). This eventually revealed the error: "System.ServiceModel.Dispatcher.NetDispatcherFaultException, System.ServiceModel, Version=126.96.36.199, Culture=neutral, PublicKeyToken=b77a5c561934e089".
I believe I 'might' be able to correct this by changing some of the settings in web.config but I'm not sure if this will work or exactly which settings need to be changed.
Has anyone else encountered this and if so could you share your findings/fix please?
Many thanks in advance,