Could this be the first sign of troubles for the VoIP Cinderella story? TeleSym announced that it had fired its co-founders and is replacing them with a new chief executive.

bq. TeleSym, a provider of software for VoIP over Wi-Fi, said founders Raju Gulabani and Karl Denninghoff have left the company and Paul Bialek has been named interim chief executive. The company wouldn’t comment on why the co-founders left. Mr. Gulabani was chief executive, and Mr. Denninghoff was chief technology officer. TeleSym has raised $18 million since its founding in May 2000. (Venture Wire)

Seattle Post-Intelligencer had published a story last week which had more details and quoted Denninghoff as saying, “Letting us both go like this was insane. It was stupid.But this is life in VC world. This is the way it works.” His stake in the company is diluted to less than 1 percent, the paper says. Gulabani and Denninghoff are former employees of Microsoft Corp. and Traveling Software, according to SeattlePI.

bq. TeleSym raised $12.6 million in a second round of financing in September. Problems started occurring a few weeks ago when Gulabani raised concerns about the lack of financial incentives provided to employees after the venture capital round. TeleSym board member Dino Vendetti led the efforts to remove the executive team, according to Denninghoff. Vendetti, a general partner at Cupertino, Calif.-based Bay Partners, referred questions to interim CEO Bialek.

It was only last month we chatted with Raju and got his take on why Voice-over-Wi-Fi is going to be a really big thing in the enterprise sector. Dartmouth College in Hanover, N.H., is using company’s SymPhone technology to wireless voice enable the students and the faculty.