An unexoected condition in the program has happened.
Contact the vendor or author of the program to ask why it failed. If you have the source code for the program, you can look at the file and line number where the assertion failed. This might give you an idea of how to run the program differently.
This message results from a diagnostic macro called assert(3C) that a programmer inserted into the specified line of a source file. The expression that evaluated untrue precedes the file name and line number.