you may want to clarify with more words than will fit in just the title....the W2 has a zero in Box 12 for Code W?

Do you mean zero wages but Code W for HSA? There were no wages, but the employer contributed to an HSA?

To clarify, the W-2 had $0 income in box 1, and the only amount on the W-2 was Employer HSA contributions, Box 12, Code W. 

ProSeries gave an efile error because of this W-2 with no income.

I read up and did some other research, and ended up not entering this W-2 in ProSeries and manually entered the Employer HSA contributions on Form 8889.  

I was able to efile, and in the long run, the final numbers on the tax forms were accurate.