install VPS update
Ver: 4.5.549
SI: 0x00000002
ST:0xFFFFFFFF
LE:0x00000000.
And where is the rest of the information?
like:
What OS?
How are you trying to update?
Is your license still valid?
How do you connect to the net?
What other security software/hardware are you using?
etc etc.
OS: Windows XP Familial
I try to update here (http://www.avast.com/eng/update_avast_4_vps.html)
because avast doesn’t want to auto-update(i don’t know why)
my license is valid
i am always connected to the net
i use ad-aware, spybot search&destroy, and i have SP2
sorry for my english.
Make sure you have no proxy set in the update settings in Avast.
Also check Avast’s log file and let us know if it has an error in there. If there is a error tell us (ofcourse).
i think i know where is the problem.
i moved the file “program files” in an other partition of my disk.
and i think avast try to update in C:/avast whereas now avast is in F:/avast.
i resolve the problems 
thx for your help Eddy
Never just move an application from one drive to another. Always uninstall than reinstall on the other drive. If you don’t and the application is using registry keys to keep track of a location (which most applications do nowadays), it will not work properly or not work at all.