The firm, Two Guys Who Do Ads, filed suit against the former Van Halen frontman in Manhattan state Supreme Court yesterday, charging he stiffed them to the tune of $110,428.91.

"He's not paying for services he signed off on," said the company's lawyer, Robert Steckman.

Roth hired the firm in 1997, and the company "set up numerous Web sites for him, did T-shirt designs for him and did public-relations work for him" - but the samurai-sword-swinging singer stopped paying his bills last year, Steckman said.

The "Just a Gigolo" and "California Girls" crooner ignored the company's requests to pay up, so they figured they might as well sue, Steckman said.

"He has a penchant for believing if you ignore something, it will go away, but it doesn't. Just look at Van Halen," Steckman said, referring to Roth's decision in the mid-'80s to pursue a solo career.

Roth's company, Diamond Dave Enterprises, didn't return a call for comment.