"They're warming her and we hope to be able to get her out sometime tonight to a hospital," Henriquez said by telephone from Boquete in Chiriqui state, adding that he did not have enough information to say whether her life was in danger. "It's raining and it's very cold."
Officials had said earlier that Lewis had already been taken to a hospital in David, the capital of Chiriqui.
Aviation authorities said the cause of the crash was not yet known, but RPC radio reported that witnesses saw the plane flying at a very low altitude around noon Sunday amid buffeting winds.
Klein, a 37-year-old hedge fund manager, was on vacation with the two girls at an eco-resort he owns in the Central American nation, according to Kim Klein, his ex-wife and Talia's mother. The three had been scheduled to return to Santa Barbara, Calif., on Monday, she told the AP from Boquete, Panama, earlier Tuesday.
But their plane disappeared after departing Sunday morning from Islas Secas off Panama's Pacific coast, heading for the Chiriqui volcano, about 285 miles west of the capital.
Rescue workers and volunteers combed a mountainous area of Panama's western Chiriqui province Monday and Tuesday, but dense tropical foliage, mountainous terrain and heavy rains made air and land searches extremely difficult, said Roberto Rolando Rodriguez, a spokesman for nation's air security agency.
Kim Klein traveled to Panama Monday morning and spoke with authorities about the possible whereabouts of the aircraft. She had offered $25,000 to anyone who could locate it.
Michael Klein, the chief executive officer of Pacificor, a Santa Barbara-based company that manages several hedge funds, founded two companies in the 1990s before becoming president and CEO of eGroups, which was the world's largest group e-mail communication service.
Yahoo purchased eGroups for $450 million in August 2000 and it is now known as Yahoo Groups.
A Klein colleague described him as a brilliant businessman who skipped high school and graduated from college at age 17.
"One of the most interesting people you could ever speak to on any ... in a myriad of subjects," Kurt Benjamin, the vice president of business development at Pacificor, told KNBC-TV in Los Angeles. "He's just an unbelievable individual."
Benjamin said Klein was close to his daughter.
"Her father was so proud of her," he said. "She was an amazing, accomplished horseback rider -- just an absolute winner. Solid, solid young girl."
--Wire services contributed to this report.