OK, here it is what I've done to make the installation happens:
# Open the Windows Registry editor (regedit.exe) browse to the following registry key: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager
# Verify the following Reg Multi String value PendingFileRenameOperations exists under this key.
Note: If you do not find the PendingFileRenameOperations value in the location above, this error message can be generated if there are pending changes in:
HKEY_LOCAL_MACHINE\SYSTEM\ControlSetXXX\Control\SessionManager\PendingFileRenameOperations
# If
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate\Auto Update\RebootRequired exists, right-click on the RebootRequired registry key and choose Export.
# Provide a different file name than in step 4 for the exported registry key and click Save
# Delete RebootRequired sub-key
(delete the value after double clicking on the "PendingFileRenameOperations" string value),
no need to restart the client just perform another push install from the server.
but how to automate this process in more than 10 clients ? sounds ridiculous if i have to send email for every affected users or even call them one by one to use regedit ?