This is usually when you have included PHP code and it has an error in it.

Nancy

Injustice anywhere is a threat to justice everywhere. -- Dr. Martin L. King, Jr.

From: Mutuku Ndeti

Warning: Attempt to assign property of non-object in eval() (line 32
of /sites/all/modules/rules/modules/php.eval.inc(146) : eval()'d
code).