Filecopy syntax

Hi guys, I'm trying to copy some files from our network share to workstations but I must be doing some stupid syntax error since it doesn't work :

Opt("ExpandEnvStrings", 1)
Local $targetDir = "%LocalAppData%"&"\Microsoft\Office\"
Local $sourceDir = "\\myserver\Office 2010\officeUI"
FileCopy($sourceDir&"\*.OfficeUI", "$targetDir", 1)

Would you have any idea as to why this is not working?

Thanks in advance!