Blockbuster may be counting down the days until it's forced to close its retail stores, the company revealed in a filing with the Securities and Exchange Commission this week. In the filing, the company revealed that it may not be able to meet the terms of a recent $250 million loan, and that there was "substantial doubt" about its ability to continue as a business in the near future.

Blockbuster's revolving and term loan agreement was amended last week, allowing its $250 million loan to mature at the end of September 2010. However, the company said in its SEC filing (summary) that its lenders won't fund the loan unless Blockbuster meets specific conditions, which may or may not happen. If the lenders decide to back out or if Blockbuster isn't able to keep things going even with the loan, the company will find itself up the proverbial creek without a paddle.

The ability to walk into a Blockbuster on a whim and rent a movie will be lost if the company goes under. In the 1980s and 1990s, the company was a true juggernaut, putting scores of mom-and-pop video rental shops out of business. For the past several years, however, the company has struggled to stay relevant amid heavy competition from the likes of Netflix, the iTunes Store, Hulu, Amazon's Video on Demand, and the plethora of other video services that have popped up. Instead of innovating on its own, Blockbuster has been stuck playing catch-up. And its staple $4.99 in-store rentals aren't so attractive in light of the $1 rentals available at the Redbox kiosks spreading across the country.

In November of 2008, the company delivered a set-top box called MediaPoint, which is meant to stream movies from Blockbuster's online library. This past January, Blockbuster announced that it would begin slapping its logo on CinemaNow's online movie service, allowing Blockbuster to deliver content over the Internet to a "wide assortment of home and mobile electronic devices." And, just last month, Blockbuster announced that its On Demand service would be coming to the TiVo. This would have been a great announcement to make several years ago, but with Amazon's Video on Demand service and now Netflix available on the TiVo, Blockbuster isn't breaking any new ground; it's just late to the party.

It's clear that Blockbuster is having trouble keeping up, and it continues to lose money in the process. We may be approaching the time when Blockbuster takes Circuit City's hand and joins CompUSA at the great strip mall in the sky.