Make sure your LinkMachine directory has all write permissions set to true.

LinkMachine is unable to write to a data or script file within your site's "linkmachine" directory itself.

See this page for a list of which files and directories need to have their write permissions turned on in order for LinkMachine to work correctly.

If after doing this you still receive the same error message, use your FTP client to delete the file lm.php inside of your site's linkmachine directory.