Calling a powershell script from InstallShield project - powershell

Question

I'm having a weird problem.
I have an InstallShield project (which creates setup.exe) that contains a custom action item - calling a powershell script.
All the script does is to install 3 adobe reader updates (1 exe file and 2 msp files) on top of the already installed Adobe Reader 11.0.0.
When I'm calling the script my self - it works fine.
However, after the setup.exe finishes, it seems like only one update (the exe file) was really installed (the adobe reader version after the install is 11.00.10 which is the result of running only the exe file..).
All 3 adobe updates sit in the same folder and the powershell script first sets it location to this folder.
When running the updates manually after the installation - it also works fine and updates it to 10.00.22 (what it should be).
Any ideas why is this happening?
Here's my powershell script:
Set-Location "C:\myProject\adobeUpdates"
Start-Process .\AdbeRdr11010_en_US.exe -ArgumentList '/q /norestart /sPB /rs /msi' -WindowStyle hidden -Wait
ping 1.1.1.1 -n 1 -w 10000 # Tried to add a delay but wasn't helpful
Start-Process -FilePath “AdbeRdrUpd11021.msp” -ArgumentList '/qn' -Wait
Start-Process -FilePath “AdbeRdrUpd11022_incr.msp” -ArgumentList '/qn' -Wait
Thank you very much

Answer 1

Solved it, this is the working script:
Set-Location "C:\myProject\adobeUpdates"
Start-Process .\AdbeRdr11010_en_US.exe -ArgumentList '/q /norestart /sPB /rs /msi' -WindowStyle hidden -Wait
ping 1.1.1.1 -n 1 -w 10000
Start-Process .\AdbeRdrUpd11021.msp -ArgumentList '/qn' -Wait
Start-Process .\AdbeRdrUpd11022_incr.msp -ArgumentList '/qn' -Wait
I'm not sure what is the different and would love someone to explain but anyway it works just fine now.