Can't open my bitcoin wallet
This sounds like your operating system thinks that your wallet file is supposed to be opened by Adobe Reader.  Adobe Reader will not know what to do with this file, so you'll get that error.  Try opening the file directly from a Bitcoin wallet, or change your operating system to recognize wallet files (.dat) as Bitcoin wallet files, and not documents.  If you are using Windows, try this: http://windows.microsoft.com/en-us/windows/set-program-access-computer-defaults#1TC=windows-7