Benchmark Capital and August Capital have successfully parried several arguments in a case brought by early investors in Epinions.com, according to court documents.

In the case Naval Ravikant et al v. Nirav Tolia, three of the company’s five founders and dozens of former employees accuse Epinions board members of fraudulently convincing them to give up their Epinions stock options just before a merger with online shopping site DealTime. The April 2003 deal produced Shopping.com, one of 2004’s most successful IPOs.

In a case management conference earlier this week, defense lawyers argued against the six causes of action in the suit filed in San Francisco Superior Court last January (see Legal Epinion). Judge Richard Kramer sustained the majority of the demurrers, effectively concluding that the original complaint doesn’t possess enough details to justify the allegations it makes.

“This decision confirms what we have said from the beginning, that this suit is frivolous and without merit. We feel vindicated by the judge’s decision and expect the court will continue to question the validity of the plaintiffs’ claims and theories as the case progresses,” Benchmark said in a statement.

Yet the defendants have a long way to go before they can celebrate. The judge gave the plaintiffs 30 days to amend the complaint and add details, something defense sources said was already in progress.

And two of the causes of action will go forward against some of the defendants. Individual defendants Bill Gurley of Benchmark and John Johnston of August did not oppose the first cause of action, for breach of fiduciary duty. The judge also overruled the defendants’ objections to the cause of action regarding securities fraud, although the plaintiffs will be amending that portion of the complaint as well.

The decision means that if the complaint is taken at face value, which the defense vigorously disputes, the case has enough merit to move forward.

The discovery process, during which both sides collect documents and depositions, will continue, and the judge ordered mediation between the parties in the interim. Lawyers for both sides will meet with the judge every few months as the case continues.