Last year Oakland Ballet canceled its season and laid off dancers because of financial problems. But this is the company’s 40th anniversary, and this weekend was opening night. “Partly to honor the history of the company, and probably to attempt to win back the loyalty of those audience members who had not taken to Karen Brown’s more adventurous programming since coming onboard in 2000, the program that ran Friday through Sunday was mostly a greatest hits kind of affair. That made it impossible to guess where the company may be going, or whether it will survive, but it was a good chance to re-examine the strengths of this plucky East Bay organization, as well as its blind spots.”