Former actress Lindsay Lohan ("former" because really, what's she been in lately other than tabloids and trouble?) is struggling to make a cinematic comeback as the titular character in a Lifetime TV movie about Liz Taylor and via a cameo in 'Scary Movie 5.'

While we're going to predict that LiLo will remain a former actress judging by the caliber of those roles, she is further sullying her tarnished rep by not playing nicely with others -- namely the producers on the horror spoof franchise.

So what's she upset about this time? La Lohan says the script makes fun of her and -- eek! -- she might have to actually kiss Charlie Sheen on-screen.

Lindsay signed up for a cameo opposite Sheen in what could be the trainwreck pairing of the ages. But Page Six reports that for the past two weeks, she has blown off rehearsals and phone calls, missed her flight to the set and even claimed to be suffering from walking pneumonia.

She eventually reported for work, but only because she was threatened with a lawsuit and because a private jet was sent to chauffeur her to the set. Nothing like reinforcing negative behavior, oh powers-that-be at Dimension Films. Well played.

The Page Six source claims that she made up the pneumonia story since being sick is a condition that could free her from her contract. She supposedly had her lungs checked to further validate her story, with doctors finding not much other than cigarette smoke, "borrowed" jewelry and the mist of a thousand self-tanning sessions gone wrong.

But never mind all that. Lohan's flack says all those claims of her being difficult are fiction and adds, "These stories are untrue, and she is willingly fulfilling all of her obligations," because that's the type of stuff he's paid to say and he's said it so often that by now he almost sounds like he's telling the truth.