What can I do. Whenever I try it says unable to save replay but It says it at top. That it's saved but it's not. In Free Mode By the way.

Are you on a mac? if so, check out this thread.

Replays can't have funny characters or names that are extremely long.

All else fails, check the permissions on your toribash directory, and make sure you have sufficient free space on the drive.

Did you save with special signs?
Like question marks or other signs?

No, It only saves my multiplayer replays. I was doing some tricking in a free play and it said unable to play.
I'm on a Dell, I didn't use special signs. I just pressed "F", typed in name. And it said failed. and I tryed a couple of times. All it said was failed.

Is this still happening?

You should provide info like how many frames & what TF you've got set.

It's happening on my long Replays like 1500 and up sp replays but not mp.

Have you tried reinstalling yet? Back up your replays first...

Also, please tell us more info about your system:

OS:
Toribash version:

There is a "edit limit" for replays, which means that after you hit the threshold your replays will turn out as they do.

(Can't recall what was the limit...)

Limit is 255 FRAME lines. I.e you can do edits to joints states 255 times.