Software Deployment

Hi. Here's the current situation i'm dealing with. I have 2 packages..
One package installs ok (Windows media player 9) when distributed via SMS, and gives good feedback. BUT, when something goes wrong (ie someone has an older version of Windows Media Player and it's running at the time of deployment) the setup still runs, completes and leaves the target pc with a non functioning media player. The weird thing about it is that when I check the event logs on the target pc, there's a windows installer message telling me the installation completed succesfully. So there could be a problem of somesort within the package. (gonna check that out..) SMS tells us that the install succeeded aswell, so this makes it hard or even impossible to get a report from SMS 2003 that is accurate.

The second package that were distributing does install succesfully, there's also a message in the target pc's event log that the install was succesfull. BUT, in this case, SMS reports a failure. probably has something to di with the exitcode the setup of that package returnes to SMS. My question; is there a way to "instruct" SMS how to interpret the exit codes some packages return? Can this be done by using status MIF's (have never used them before) created using Wfwi, or is there an other way? If so, is there a guide of some sort available online on how to get started using status MIF's? Or is there another way of getting the right feedback using SMS? Any help would be greatly appreciated. TIA!
Kind regards