The company disclosed it had found more accounting irregularities as part of an internal probe. This is the second time the cable operator has disclosed additional problems on top of the June disclosures that led to the opening of a Securities and Exchange Commission probe and the firing of 14 employees. The company said in June that employees at the Rainbow unit improperly accelerated $6.2 million in marketing expenses and fabricated invoices.

This time, an internal audit, led by law firm Wilmer Cutler & Pickering, discovered $15 million in improperly booked expenses from 2002 or before at its Rainbow Media Holdings unit, which includes cable networks American Movie Classics, Independent Film Channel and WE: Women's Entertainment. The company will restate this year's first- and second-quarter results and revise Tuesday's third-quarter posting to reflect the improper bookings when the probe wraps at the end of this month. While Cablevision warned that ''additional amounts'' might be found at Rainbow or other units, it told Wall Street analysts on a conference call that Wilmer Cutler has ''substantially'' completed its investigation.

Cablevision executives said the company is weighing whether to restate quarterly and annual results for 2000 to 2002 and is evaluating the impact of the improper booking on the separate financial statements of its subsidiaries.

The broadening troubles might complicate Chief Executive James Dolan's proposed 2004 spinoff of the Rainbow networks, along with Cablevision's recently launched satellite broadcasting service VOOM. That cannot proceed until the SEC completes its investigation.

The Bethpage, N.Y.-based company also services 3 million cable households, mostly in the New York area, and it owns other properties that include Madison Square Garden, Radio City Music Hall, Clearview Cinemas, and the New York Knicks and New York Rangers pro sports teams.

Blaming weakness in its core cable business in New York City, Cablevision posted a third-quarter net loss of $105 million, or 36 cents per share, compared with a net loss of $79.5 million during the same quarter a year ago.

Revenue increased 12% to $976 million from $872 million. That beat Merrill Lynch's estimate of $960 million, according to analyst Jessica Reif Cohen.

Rainbow Media's core networks posted a 17% increase in revenue and 45% boost in adjusted operating cash flow. Dolan attributed that to strong growth in ad revenue, particularly at AMC and WE.

Cablevision shares closed up 2 cents at $20.45.