I ran into a problem with cascading deletes that appeared after an upgrade from MySql 5.1.50 to 5.1.51.
Deleting a row from table a with a cascading delete that results in more than 250 rows being affected in table b will give the error
Got error -1 from storage engine
The solution is to either wait for a fix to MySql 5.1.51, downgrade to 5.1.50, or to first perform a query to delete rows in table b referencing the row in table a before that row is deleted.
The bug report is found here
If someone else runs into this issue, hopefully you'll save time by this information, and sweat less than I did when the bug reports started rolling in.