BUG #3901: Received error

The following bug has been logged online:

Bug reference:      3901
Logged by:          Chris Hoover
Email address:      revoohc@gmail.com
PostgreSQL version: 8.3.rc2
Operating system:   RHES 4.0
Description:        Received error
Details:

I just received this error on my command line.  I think this came from
postgres as it is the only app running on this server.  I am not sure what
caused this since the server was idle.

TRAP: BadArgument("!(((header->context) != ((void *)0) &&
(((((Node*)((header->context)))-
>type) == T_AllocSetContext))))", File: "mcxt.c", Line: 589)