Does it oNLY crash after loading another level? Or does it sometimes crash on its own?

It may be that these "other" levels are not being completely 'released' when you
load your 'naughty' level, and so there is not enough space left to fit it in?

Have you tried multi-loading just the naughty level? And checking for crashed or 'extra' memory consumption.
Code:
while(1)
{
   level_load("naughty.wmb");
   diag_memory_usage();
   wait(-10);
}
That may expose an in-engine memory 'leak'...



"There is no fate but what WE make." - CEO Cyberdyne Systems Corp.
A8.30.5 Commercial