"That film wasn't too successful, but then 'WarGames,' which was successful, came out right when I won the Tony for 'Brighton Beach' in 1983.
The film that wasn't too successful isn't named in the sentence. 
I'm not sure why it was difficult. The film that wasn't successful is never mentioned in the sentence, instead it talks about two films that were successful, so the statement is correct. 
( z1 name :polarity - :ARG1 ( z2 film :ARG1-of ( z3 succeed :polarity - :ARG2-of ( z4 have-degree :ARG1 z2 :ARG3 ( z5 too ) ) ) ) :location ( z6 sentence ) )