There is a conflict in the project metafile (.PJM file).
You edited the .PJM file directly.
Restore the file to a previous version and use the interface to make changes: undo the checkout of the .PJM file and update the project list.
There is a conflict in the project information section of the .PJM file.
Resolve the conflict by removing complete lines only, if possible.
The formatting in the project metafile is incorrect.
For example, some information has an unexpected data type, or commas are misplaced.