Eggdrop reports one of 2 error messages, when working with large memory loads. Either a memory table full (eggdrop internal limit, to the amount of memory it will use. This is designed so that eggdrop doesn't hog the whole system (this value can be changed when compiling)).
The other error, is the one you received. This happens when eggdrop was refused any extra memory it needs. This can be due to hard limits per user or the fact that the system ran out of memory it could give to the eggdrop.