Wondering if this is an error and why I'm getting it.
Also the bot says "tested 10,000"
does that mean its checked 10,000 times on the names?
No 0x19 isn't an error, its the bot checking to see if your account list is full by requesting to see how many characters are on your account. It does this because the bot then switches to a new name when the old name is full.
And the counter means how many times the bot has attempted to make a character. So in your case, since you started the bot, it has attempted 10,000.