I would suspect that you might be missing a file for the C-130's. You might want to check your Anti Virus software for any Captain Sim files that might have been removed post installation.

Once you turn your AV back on and start FSX-SE, it might have removed a file that it considered a threat (false positive).

When selecting a new aircraft, can you see Captain Sim in the Publisher list? Do you have any other Captain Sim products, or is the C-130 X-Perience (FSX) the only one? If you do, are you able to select them, and do they show up like they should?