I doubt if there's a program to unencrypt a Windows Mobile encrypted file on a PC.
In that case, the solution would be to open the file on your phone (which still can) and save it as an unencrypted doc. Then move that to where-ever you want. It's some work, if it are a lot of files, but if the content is important enought it might be worth the trouble.
Our general recommendation is to have an unencrypted backup copy of encrypted files stored in a safe place, just to cover circumstances like this.
I used to encode files on my WM6.x device. A word document i.e. fred.doc would be renamed as fred.doc.enc and could be decrypted with a password. This is deifferent from the auto encryption which were hash tagged to the device i.e. fred.doc.ef1212fh12.enc.
Is there a program on the PC that, with the valid password of course, I can decrypt my own data - or has Microsoft once more left me in the lurch?
Any answer would be greatfully recieved before I retire my WM6.x device and move into the Android world.