is either location a/b null when there is a value of mrs-moe....nulls are treated as errors, it seems, but not reported.
you might try something like:
local booleanvar mrsmoe:=false
if Not isnull({Table.Location_B}) AND {Table.Location_B}= "mrs-moe" then
mrsmoe := true;
if Not isnull({Table.Location_a}) AND {Table.Location_a}= "mrs-moe" then
mrsmoe := true;
if ({Table.Create Date} in LastFullMonth
or
{Table.Closed Date} in LastFullMonth) and mrsmoe then...
HTH