A man who fell and injured himself on SHARON STONE's estate is suing the actress for unspecified damages.
 
Peter Krause claims he fell down a "large, concealed drop-off" while at Stone's home in 2006, and he has been fighting pain from his injured ever since.
 
But the Basic Instinct star and her aides are baffled about the lawsuit - because they have no idea who the guy is.

A representative tells TMZ.com, "There's no record of this individual being on the property and likewise there's no record reporting this individual being injured on the property.
 
"Neither Ms. Stone or her attorneys have seen a copy of this complaint."