There is growing skepticism among investors if Research In Motion (RIMM) will be able to pull off its “Playbook” tablet as anticipated reports CNBC. Investors sent shares of RIMM tumbling after the company warned of weak profit and revenues in the short term.

Investors are skeptical that the company can take on Apple’s iPad when it is having a hard time with its core business – the BlackBerry.

RIMM has spent heavily developing and marketing the yet to be released device, designed to take on Apple’s iPad in a now crowded tablet market. The device is also much smaller (7 inch screen) than the iPad (9.7 inch screen) for the same price.

Investors are also unsure the BlackBerry maker can pull off a difficult transition from a phone maker to a tablet (few have seen) maker.

Brian Modoff, analyst with  Deutsche Bank (a believer in RIMM) suggested clients sell their RIMM shares.

Modoff, among others, believes it’s imperative that RIMM move quickly to release its touch-based BlackBerry smartphones, replacing an outdated platform that’s ill-equipped for today’s data-heavy applications. However, RIMM said that there is no chance of a touch-based BlackBerry smartphones until next year. The big question is whether the touch-based BlackBerry smartphones will impress (when they finally come out) when stacked against the competition.

Investors were further rattled when RIMM announced that the launch of the Playbook would hit the company’s gross profit margins and they would likely not recover anytime soon.