Msiexec - passing a path to it...?

I am trying to launch msiexec to install a package.
If I launch it from a CD disc, then it works fine.
If I lanuch it on the network, it fails.

Its a question about paths I think.
I wonder if msiexec.exe can handle easily network paths , especially if I pass it:

msiexec.exe /package \\myserver\Installer3rdPartyInstalls\myinstaller.msi

This works ok:
msiexec.exe /package c:\Installer3rdPartyInstalls\myinstaller.msi

looks like one of those times I am about to answer my own question:

this worked:
ExecWait '"$WINDIR\System32\msiexec.exe" /package "$EXEDIR\Installer3rdPartyInstalls\myinstaller.msi"'