Dealing with IRS files from years prior to 2008 can be difficult, the issue is historical, files prior to this were worked in Cas and LOAS, older software systems.
Offices will not be able to add these files in the normal fashion (using add office manuals)
The workaround is to zip up the IRS file and then save the zipped file into the Analysis_Recieved_Files folder on the server. then in IAS you simply click add files from analysis, this will add the 07 file to the file list, at which point you will have no issues.
Regards
Oscar