Code:
self.frame = _G["stuf.units.party"..self.id]
"stuf.units.party3" is not a global name. "stuf" is the global name of a table, and "units" is a key in that table, and "party3" is a key in
that table, and the value stored under that key is a reference to the unit frame you want. You can't look it up the way you wrote, though. Either:
(1) Type "/fstack" and move your cursor over a party frame to find out what its name is, and change your code accordingly. For example, if the name is
"stufomglolcatsandlasersharkstrexparty3", then your script needs to look up
_G["stufomglolcatsandlasersharkstrexparty"..self.id]
(2) Dispense with the
_G lookup and change that to
stuf.units["party"..self.id] instead.