After getting a call logged with Microsoft the resolution I was given (although still under investigation at MS) was to re-install wimgapi.msi from the WIM folder within the folder where config mgr was installed too. This has worked for me. This appears to be a problem that has previously happened in config mgr 2007, I found a TechNet article for it. I cannot paste anything into this topic for some reason, but search TechNet for BB932179, it describes re-installing wimgapi among other things.