Here is the extract from page two of Form I-485 (you can download the form from the BCIS website at URL:
http://www.bcis.gov/graphics/formsfee/forms/files/I-485.pdf)
"Affidavit of Support/Employment Letter.
Affidavit of Support. Submit the Affidavit of Support (Form
I-864) if your adjustment of status application is based on your
entry as a fiance(e), or a relative visa petition (Form I-130) filed
by your relative or on an employment based visa petition (Form
I-140) based on a business that is five percent or more owned by
your family.
Employment Letter. If your adjustment of status application is
based on an employment based visa petition (Form I-140), you
must submit a letter on the letterhead of the petitioning employer
which confirms that the job on which the visa petition is based is
still available to you. The letter must also state the salary that
will be paid."
Two things are clear:
1. If at all you need an affidavit of support, it is form I-864 (NOT I-134). This can also be confirmed by reading the instructions for those two forms.
2. For EB cases, you dont need an affidavit of suport (unless the employer is a business that is five percent or more owned by
your family).
K.S.