"All commercial paper [check in this case] must be presented either to the maker of the note or the acceptor of a draft in order to get money for the paper. If, after presentation, the party to whom presentment was made [the bank] fails to pay [because account was closed], it may be desirable to proceed against the drawer [company] or indorsers [you]."
"If a check is drawn with intent to defraud the payee [you], the drawer [the company] is civilly liable, as well as subject to criminal prosecution in most states under so-called "bad check" laws."
(Ascroft, Law for Business, 11th ed).
In a nutshell, since you indorsed the check over to the casino, you are responsible to the casino for payment. The company is then responsible to you for payment. The casino is going after both of you because they don't care who pays it, just so someone does. I would suggest that you pay back the money, get the check back, and then call your State's Attorney General's office and proceed from there.