Hello,
I have geckos, golden geckos (gekko ulikivoskii), they climb walls as well.
I forget the term for their feet.
But they have tiny hairs on their feet (stating the obvious, I just don't feel right not explaining EVERYTHING in a post) (sorry).
When the tank walls are wet, they cannot climb them, unless they're crazy ninjas.
The tiny hairs get wet and squish together (or whatever you call it).
If that's not it.
Then you may want to take out the gecko, try to get her to lay on her back so you can examine her feet.
Are you using anything that could possibly burn her?
A light wouldn't do that, geckos are smart enough to not climb on the ceiling when it is hot.
Are there any tankmates?
If so, you may want to think about the possibility of a fight.
Nipping is very common with many lizards.
Another way to examine the gecko's feet, is to hold him/her up to a clear glass wall, preferably one you can stand behind to watch as well.
And try to get her to attempt to climb, if she does attempt, watch her feet very carefully.
I hope I've helped, by the way, my geckos are 8 and 7 years old, how old is your's?
Goodluck!
Bye.

-collin