hy, a scuccess in the server webgui doesn't mean that the package was really installed. It only means that there was no error in the script you deploy.
You must deploy a batch script which logs everything localy - so you can see what is going on.
for example put something like this in a batch file with cmd extension and use the launch button for deployment in OCS-Inventory
msiexec /i "C:\MyPackage\Example.msi" /L*V "C:\log\example.log"
it would be helpfull if ocs-inventory has the capability to log everything on server.
Sometimes i do some logging to a central fileshare to watch what is going wrong