Looks like you're running your for loops from 0, for sourcemod when you're dealing with clients be sure to start from 1 because client index 0 is the server.
An example of this is...
PHP Code:
for (int client = 1; client <= MaxClients; client++) {
PrintToChatAll("%N", client);
}
For the array errors, I presume you're formatting the arrays like this:
PHP Code:
char clientName[MAXPLAYERS];
The code I've seen doing things like this normally use:
PHP Code:
char clientName[MAXPLAYERS+1];