[SQL] I get an error with Foreign Keys

[Brian Powell]

I have around 40 tables defined, many relying on data in others so I have
foreign key constraints.  However, whenever I try to delete from any table,
I get:

ERROR:  SPI_execp() failed in RI_FKey_cascade_del()

What generates this?  I need assistance in knowing where to begin.  I
checked again, and I could not find any circular foreign key constraints...

Any help on where to search is appreciated.

Thanks,

--Brian