If you really can't locate the PA employer tax ID number, I would use the federal employer ID number and see if your tax return will be accepted, assuming you are e-filing your PA tax return. If PA rejects your e-file, then I would simply paper file it and attach a copy of the W-2 form.
I would not enter the W-2 income as "Other income". I assume this is some sort of a W/C lawsuit. Good luck!
