Why it doesnt want to update

[EightyVice]

i have the version 04rel003_4 and when i open any server it show downloading dialog and when it completed
it says

Failed to rename new installation

[MacTavish]

erase all 04rel00x folders and open VCMP browser it will download necessary updates

[KAKAN]

erase all 04rel00x folders and open VCMP browser it will download necessary updates

Nah, no need. Just run the vcmp browser as administrator. If you're running out of space, then follow's @MacTavish technique

[Thijn]

Try the above methods first, if the update still fails you can download the latest version on my site here: http://u04.thijn.ovh/
(You'll want 04rel003)