As Marttt said,
PHP Code:
if (!StrEqual(auth, "BOT"))
(prefer using double quotes for strings, and single quotes for a single character, else you might encounter some bugs)
You can however check a single character like this:
PHP Code:
if (auth[0] == 'B')
(the single quotes are mandatory here)
Similarly, please use strcopy() or Format() or FormatEx() to write into strings, don't directly assign them.