Since I do not believe that Colorado uses a state database, but instead uses NICS, simply file a NICS appeal. The gun dealer should be able to help you out with that. The computer probably saw the case and automatically denied it and, via the NICS appeal, is going to take an intelligent human to dig deep enough to determine the real circumstance and reverse the denial.
After that, you can get a NICS PIN number (I think) and be able to breeze through the NICS process in the future with no problems.
Here's some more info: