Without having the service manuals in front of me, and having not worked with Icom gear in about 10 years I'd venture a few guesses based on my experiences:
Likely, the programming software and the radio firmware are not compatible. Best way to address this is to call Icom and give them the specifics. The firmware and serial number of the radio and the software version level will be needed. Icom can tell you if you need a different software version, new radio firmware, or both.
Maybe someone with some more recent Icom experience can confirm or deny that. Either way, Icom has a toll free number and they should be able to answer the software/firmware version question pretty quick.