"To avoid havoc and disaster". The Umno elections, initially scheduled for last year, were postponed to this year due to the 12th general election on March 8. The last party elections were held in 2004.
Under the party's constitution, Pak Lah can postpone the elections up to June next year.
Read Bernama's story, quoting Muhammad Muhammad Taib, here. He failed to explain, however, what havoc and disaster would befall us if Umno holds its general assembly and election this August.