Installing Pd extended on a new laptop (win8), I get the GL invalid enumerant error.
It fills the message screen, so you connot debug your patches.
A temporary solution:

Change the level of error messages. It's at hte bottom of Ps's main window, to the right of the Tcl box. Where it says

"Log: 2" change to "1 error"

so you only get error messages, and not warnings.

It's only a temporary solution, waiting for a real fix of the problem.