Thank you Vince and John for the input….
However, I guess the joke is on me.
Discovered the actual error to be occurring on the ELSE portion of my IF statement. Where I was Null’ng out my field, I was using the PATHCOPY @null to outputfield (normally works great), but I guess this is not allowed in an .frl to hl7 Xlate even although it is not referencing infield to outfield.
I changed this to a regular COPY @null to outfield and it worked – no more panics
Thanks
Andre