[MP2]

tolower takes a character as a parameter, not a string. You need to loop through the string and use tolower() on every individual character.

EDIT: StreetGT beat me. I'd suggest some minor changes though:

pawn Код:

public NickToLower(const nick[])
{
    for(new i=0, j=strlen(nick); i<j; i++)
    {
        nick[i] = tolower(nick[i]);
    }
    return nick;
}