Well five years later and Easy Interactive Tools is still a problem for some. So after fighting with the silent install over the network I noticed that it installs fine locally. Turns out it's a permissions thing. The install wants to write back to the share folder but doesn't have permission to so it never installs. If I log on as a domain admin the silent network install works. I want the install during startup so ended up copying the setup folder locally and the run install.
xcopy /h /e /y /i /c /d "\\srv-share\Programs\Brightlink\Silent_EIT_5.00" "C:\Windows\Software\Brightlink\Silent_EIT_5.00"
"C:\Windows\Software\Brightlink\Silent_EIT_5.00\InstData\setup.exe" /s