So your having problem saving the chirp file that you created. Question is can you save in other applications? For example can you save somthing in notepad? NO same error  ? then its something with your operating system. If yes then its not the OS but its pointing towards the software. Remember its BETA.. which means it may be something that does not like your hardware or something like that. Make sure you have the current version of CHIRP. Try removing and reinstalling.. make a small file so as not to waste time adding a lot of information in. Can the software read the information in your radio ? Are the drivers installed correctly? Check your MSCONFIG file for anything that might be a problem with your system. Temporally, pause your virus program.. Try these tips one at a time to find out if any of them work. Have you tried the software that comes from the manufactor of your radio?

You have to try determine if the problem is with your OS or with the program.
Hope this helps.