Shares of colorful plastic shoes maker Crocs Inc. (NASDAQ: CROX) have been plunging this morning, despite the firm posting strong fourth-quarter profit. Hurting the stock this morning is the company's 2008 guidance, which came in slightly below analysts' predictions. As Timothy Sykes discussed, Crocs impressed with its international growth but failed to raise its outlook for the year.

Crocs reported last night that its profit during the fourth-quarter surged 84% to $38.3 million, or 45 cents per share, boosted by higher international demand that nearly doubled its revenue. Its earnings per share were a penny higher than analysts' forecast of 44 cents per share.

For its quarterly revenue, Crocs posted an impressive jump of 99% to $224.8 million, up from $112.9 million in the year-ago period. Revenue during the period was helped by a 47% rise in the United States sales. International sales more than tripled to $109 million.

However, investors' enthusiasm over the company's earnings figures didn't last long. After posting better-than-expected quarterly earnings, the footwear company disappointed investors by reporting a lower gross margin.

Crocs said its decision to use more expensive air delivery for transporting the Mammoth, a new type of winter shoe, in the face of unexpected demand during the holidays hurt its gross margins.

Over the past few months, Crocs had to face consumer worries over the safety of its signature shoes and also patent disputes in Europe that brought increased pressure on its shares. Based on current consumer spending fears, the company's outlook for further gains is not too encouraging.

Crocs backed its previous 2008 guidance, predicting profit and revenue below estimates. The company now expects first-quarter profit of $2.70 per share, on revenue of $1.16 billion. This was below analysts' forecast for a profit of $2.72 per share on $1.16 billion in revenue.

Crocs' pessimistic outlook brought more pressure on traders who are already concerned over a weak U.S. footwear retail space and pushed the stock shares down over 17%. As a big part of Crocs' footwear sales are coming in the second and third quarter, it is still unclear how much the seasonal variation will impact its earnings numbers.

Eliza Popescu is a financial writer for the online investment advisory service Investor's Observer.