No no, don't change any paths unless you know exactly what you are doing.
What kind of program is it? I assume it is a console program consisting of a single unit. In this case, copy this pas file to a new folder (just to keep the original), open it in Lazarus - you will be prompted for a project template, select "Simple program". Select "File" > "Save as" to save to the new name that you want. Compile and and run -- it must work. If it does not something is wrong in your installation. In this case uninstall the old installation, delete the config folder (in Windows in c:\Users\<your name >\appdata\local\Lazarus, in Linux in ~/.lazarus) and reinstall again.
BTW, what is your OS?