I think you are running the GameServer compiled in Debug mode and I guess you recompiled the GameServer from its source code.
That's an assertion error which is used in debugging variables.
It's like an IF statement but at debugger level.
That error is coming from a variable called "c" and it's triggered everytime when c >= -1 and c <= 255 (any value from -1 to 255 is triggering that and I think that's a left over which someone forgot inside or it's in fact an iterator from a string or char).
Code:
if ( c >= -1 && c <= 255 )
{
//Display the error message box
}
Code:
ASSERT(logical conditions);
Anyway, an example of what can possible trigger the error:
Code:
char username[100];
for( int i = 0; i <= 100; i++)
{
username[i] = "A";
}
If your "i" reaches 100 and is trying to access the char at "username[100]", it's gonna trigger the assertion error which is actually coming from isctype.cpp. It's an out of bounds error.
Probably a fix:
Do a recompile of your GameServer in the Release mode, not Debug mode.
If it's still showing that error, see the call stack of your functions to see from where the assertion came from and see what's up with that variable which is used in that check.
It can be an account name or char name being invalid or with bad encoding which GameServer doesn't know.
Edit: What season are you trying to set up and what files (links or whatever to point to them)?