It's probably not a factor any longer, but just in case...
A few threads ago you remarked:
"...they mispelled her Mothers name on my finacee's birth certificate when it was originally issued."
I just re-encountered the same USCIS page that mentions such a scenario, and here is what they have to say about it:
"If anyone’s name has been legally changed (if it differs from the name on his or her birth certificate), evidence of the name change must be submitted"
http://uscis.gov/graphics/howdoi/childproc.htm#usstepparent
It's the final italicized stipulation listed under nearly every petitioner/beneficiary scenario presented.
Peace out!