did you try to go through the usual "why" and "where" routine with your errors?
A number of fatal error codes with symbolic names are documented in the *.FEI
files in the TCL directory, and more info on them will be shown when you type
"why" after a fatal error.
I found that using the backtrace shown by "where" or "backtrace" is still
helpful even if dealing with an error code that has no symbolic name, because if
you go back to the stack frame before FatalError, you can have a look at the
code that ultimately invoked the error routine - in many cases, using this with
a little guesswork (what object does DS:SI or ES:DI point at? what instance
variable has been checked when the error was called?), this may give you a clue
into the right direction. Anyway, this usually requires you to get deeper into
the system than is desirable for an often relatively simple problem.
If nothing helps, can you post the backtrace from the error location?
ciao marcus