Hello, I have a GC interview at the US embassy next month but my employer is not willing to sign an employment letter with the wording of " hiring on a permanent basis" or something to that effect and has only given me a letter stating my current position, salary, and job discripton. Is this lack of " permanent basis employment" wording material for my application to come through? Has anyone here obtained their green cards with a generic employment letter? Thanks a lot in advance!

Some employers are worried that stating permanent in the wording means they are legally required to hire you and pay you on the permanent basis. If they refuse to word it that way, you do not have much choice, since it is their document. Try submitting the letter that the employer is comfortable with and see if USCIS is fine with it. If not, they can issue RFE and you can talk to employer about it.