I have a Document Library that has three different Workflows. I am attempting 
to create a calculated column that will evaluate to "Yes" if any of the 
Workflows have been approved. (Evaluated to 16, the value of the Approval).

However, when ever I try to use the column, I get this error:  One or more 
column references are not allowed, because the columns are defined as a data 
type that is not supported in formulas. 
 

This is my ultimate formula: =IF(OR([Pre-Approved Change 
Approval]="16",[Standard Change Approval]="16",[Emergency Change 
Approval]="16"),"Yes","No")

But I get the error with just this too:  =[Pre-Approved Change Approval]

I have seen that the "," really needs to be a ";" and I will change that 
when I test further... I also found some posting there that a Document 
Library list is different in some undocumented way than other lists.

Why can't I use the columns from the Workflows?

Thanks,
Doug