Unable to install AIR

I have trouble installing Adobe AIR, and the installer just quits with the error "An error occurred while installing Adobe AIR. Installation may not be allowed by your administrator. Please contact your administrator". (I am the administrator on this computer).

The installation log:
*****************************************************
Performing runtime install
UI SWF load is complete
UI initialized
enter confirming
Installation type: new
stateInstalling: enter install
Scheduling runtime installation operations
Beginning runtime installation
Beginning install
Installing C:\DOCUME~1\geilin11\LOKALE~1\Temp\AIR42.tmp\setup.msi
Uninstalling product w/ GUID {BB8B979E-E336-47E7-96BC-1031C1B94561}
Error occurred; beginning rollback: [ErrorEvent type="error" bubbles=false cancelable=false eventPhase=2 text="1605" errorID=0]
Rolling back install of C:\DOCUME~1\geilin11\LOKALE~1\Temp\AIR42.tmp\setup.msi
Rollback due to error complete
stateInstalling: [ErrorEvent type="error" bubbles=false cancelable=false eventPhase=2 text="1605" errorID=0]
runtime install entering error state: [ErrorEvent type="error" bubbles=false cancelable=false eventPhase=2 text="1605" errorID=0]
*****************************************************

I have had betas installed previously, but I have tried to uninstall them both by the Add/Remove panel and by using the Windows Installer Cleanup utility linked a couple of times here on these forums. Still no luck.