Lindsay Lohan -- I'm Not a Trailer-Trashing Toilet Clogger!

Lindsay Lohan says she's been framed -- she couldn't have trashed her "Scary Movie 5" trailer ... 'cause it was trashed when she got there, and producers retaliated because they were pissed off she was a no-show for the first day of shooting ... so Lindsay is telling close friends.

Lindsay is pissed at reports claiming she clogged her toilet -- along with all the other toilets on the set.

Now here's Lindsay's story -- she's telling friends producers were ferociously upset she missed the kickoff day ... even though she told them she had walking pneumonia and doctors ordered her NOT to fly.

We're told when she arrived belatedly, the trailer was a disaster -- the shower and toilet were not working ... and she had to do her biz in adjoining trailers.

It was only after the shoot that Lindsay was accused of wreaking plumbing havoc and told she would not get her full paycheck ... to cover repair costs.