Delete [project].pro.user in your project directory
move your directory to a root with no spaces in the name. For example it's better for your project directory to be placed where like "c:\myproject" on windows.
Which IDE are you using? Are you trying to import a project in Carbide? If it is carbide I faced the same problem months back. I deleted all the built files and related files in epoch32 folder. Sorry, i lost that link which explained all these and i stopped using carbide.