Linking Tables

Hey, 

I am having a bit trouble adding a column to the Manufacturing> Inquiries > Products. Screen code: CONSMKI2. I am trying to add the field REFPER from the table STOLOT. In the script I have added the following code:

##############################

Read [F:STL]STL0 = [M:MKI2]ITMREF(NOL)
If !fstat
[M:MKI2]REFPER(NOL)= [F:STL]REFPER
Else
Raz [M:MKI2]REFPER(NOL)
Endif

##############################

But it is not populating anything. I think the problem is how I am linking the table. I don't really much experience linking tables so any help I can get would be greatly appreciated. 

Thanks!