Running EXE/MSI from Network is very sluggish

When running my Install MSI/EXE from a network drive it takes upto 2 minutes
for the Installer Welcome screen to show up. Have confirmed same thing is
happening on multiple PCs.

Below is my install log file which points to SOFTWARE RESTRICTION POLICY
taking that time.

Any ideas how to troubleshoot and reduce the time?

As such we are not using any custom software restriction on our server
(Windows 2008 SBS or Clients Windows 7 PCs).

=== Verbose logging started: 7/30/2010 15:06:23 Build type: SHIP UNICODE
5.00.7600.00
Calling process: \\myserver\Users Shared Folders\Anup\JP7\Main
Installer\Install.exe ===

MSI (c) (C48) [15:06:23:494]: Incrementing counter to disable shutdown.
Counter after increment: 0
MSI (c) (C48) [15:06:23:504]: SOFTWARE RESTRICTION POLICY: Verifying
package --> '\\myserver\Users Shared Folders\Anup\JP7\Main
Installer\Install.msi' against software restriction policy
MSI (c) (C48) [15:06:23:534]: SOFTWARE RESTRICTION POLICY:
\\myserver\Users Shared Folders\Anup\JP7\Main Installer\Install.msi has a
digital signature
MSI (c) (C48) [15:07:10:954]: SOFTWARE RESTRICTION POLICY:
\\myserver\Users Shared Folders\Anup\JP7\Main Installer\Install.msi is
permitted to run at the 'unrestricted' authorization level.
MSI (c) (C48) [15:07:10:954]: Decrementing counter to disable shutdown. If
counter >= 0, shutdown will be denied. Counter after decrement: -1
MSI (c) (C48) [15:07:11:154]: Cloaking enabled. MSI (c) (C48)
[15:07:11:154]: Attempting to enable all disabled privileges before calling
Install on Server
MSI (c) (C48) [15:07:11:174]: End dialog not enabled

Thanks