Amazon.com Inc.'s (AMZN) Kindle electronic book reader may not be all its cracked up to be.

That's what one Seattle area customer claims in a lawsuit filed Tuesday that alleges his $359 Kindle 2 has cracked and its screen froze only a few months after purchase. The lawsuit, filed in U.S. District Court for the Western District of Washington, seeks class-action status and says damages could exceed $5 million in refunds, treble damages and legal costs.

Matthew Geise, a Seattle real estate executive, says he bought a second-generation Kindle for his wife and the device's screen started freezing after cracks developed on the frame. The cracks appeared near where the official Amazon leather cover attaches to the device with metal clips.

Beth Terrell, Geise's lawyer, acknowledged in an interview that she wasn't sure whether the screen damage was caused by the cracks.

The lawsuit is a first chink in what has largely been a huge success story for Amazon. Citi analyst Mark Mahaney has estimated Amazon's Kindle-related revenue could reach $1.2 billion by 2010, or roughly 5% of the company's sales next year. Amazon wasn't immediately available for comment on the lawsuit.

Amazon does not release Kindle sales figures, making it much more difficult to estimate the number of customers who might be part of the class action. The lawsuit states that Internet complaint boards and product review sites contain scores, if not hundreds, of complaints from Kindle owners whose devices have been damaged by their covers.

"I think it's a much bigger problem, given the number of posts going up everyday," said Terrell. "These are just the tip of the iceberg."

The lawsuit states that Geise called Amazon to make a warranty claim and was told by a customer-service representative the company would repair the screen freeze but not the cracks because they were caused by improperly opening the cover backwards. Geise, who said in an interview that the Kindle was not improperly opened, was told he would have to pay $200 for repairs.

The lawsuit also states that an Amazon supervisor later told Geise's wife that cracking of the Kindle was a "common problem."

Shares Amazon rose 2.3% to $83.85 in midday trading.

-By Scott Morrison, Dow Jones Newswires; 415-765-6118; scott.morrison@dowjones.com