I doubt the error is because of this code.
This error is more you use too much entities at once. There is a limit which can be calculated like this :max_entities = 900 + 15 * ( max_clients - 1 ).
You can define a custom value to up the limit using the switch "-num_edicts" in your line command line. eg :
[...] -map blabla -num_edicts 2047
If you can't it's probably a plugin badly coded which don't remove properly entities which create or a plugin which create too much entities at once.
About the black fade, you maye be interested by this
stock.
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