You seem to use SVN for version control system. This happens when you checkout some code, modify it and before you commit it someone else commits the same file. If SVN fails to merge your and someone else's code it leaves different versions of files in the directory where you checked out the code (e.g. script.pl.mine, script.pl.r914 etc.)

When it happens with me I just remove all the versions of the file (script.*) having different extensions, check out the code again, merge my changes in the updated file and commit it before someone else do it again. :-)