hi everyone, just in case someone else runs into this problem in the future, here is what i did to find the problem of the API error message.
i followed 'jseelenbrandt' instructions above, and tried posting the item through ebay. when i clicked to submit the ad, an error message popped up informing me why my add couldnt be posted. for me it was stating that i was trying to accept money gram as payment, when in fact i was stating that i would NOT accept MG for payment. so im assuming ebays filters operate only on keywords and not entire statements.
this method helped me. hope it works for you guys also!