Upon closer inspection, noticed a few other things that might be causing issues.
You have a def called "concat(nf)", but the Expression block says "conact(!ParcelNum1!)" which is spelled incorrectly, so shouldn't even run that def. (also spelled this way in the search cursor which could cause it to not open TableTest6 if the field in the cursor doesn't exist)
also, sending !ParcelNum1! to it ( conact(!ParcelNum1! )), which, according to the table you supplied doesn't exist. It says ParcelNum.
also, !ParcelNum! is a field getting passed to the def as "nf", but I see no iterator to go through the rows of that field to evaluate it. I think it is the dictionary you are wanting to iterate through, not a field. Might need something like:
for key in dict1:
x = ",".join(dict1[key])
And, I've never put stuff in the Code Block outside of a def before, so not sure if that would even run (though, the error tends to suggest it is). I would move all of the code within the def to ensure it runs, and in the order expected.
R_