Research In Motion shares plunged Friday as the struggling BlackBerry maker said it will not meet its annual earnings target and it is taking a $485 million charge because of weak sales of the PlayBook tablet computer. The Waterloo, Ontario-based smartphone and tablet manufacturer, said it no longer expects to meet its full-year adjusted earnings guidance of $5.25 to $6.00 a share. RIM shares were down 8.61 percent at $16.98 in early trading on Wall Street and shed six percent to $17.36 on the Toronto stock exchange. RIM said it would take a pre-tax charge of $485 million in the third quarter of its fiscal year because of a write-down in the value of its \"high level\" of PlayBook inventory. The company said it was also taking a charge of $50 million in the quarter, which ended November 26, related to a BlackBerry service outage in October. RIM said third-quarter revenue is expected to be slightly lower than the previously forecast $5.3 billion to $5.6 billion. Earnings per share are expected to be at the \"low to mid point\" of the $1.20 per share to $1.40 per share range forecast previously, it said. Sales of the PlayBook have been sluggish since the device hit stores in mid-April with a $499 price tag for the 16-gigabyte model, $599 for the 32GB version and $699 for the 64GB model. Major US retailers Best Buy, Staples and Office Max slashed PlayBook prices to $299, $399 and $499 in September but the device has failed to make inroads in a market dominated by Apple\'s iPad. RIM said it sold 150,000 PlayBook tablets in the third quarter and 14.1 million BlackBerry smartphones, in line with its previous guidance of between 13.5-14.5 million.