Getting sick of my questions yet?!

Ok, so same installer, Company_setup.exe, a webmedia basic MSI that downloads the .msi and .cab files from our server, and has 2 prqs, 1_setup.exe and 2_setup.exe. Works perfectly on my test computer, both as a fresh install and as an update over existing installations, on XP, Vista and Win7. No issues.
On the owner of our company's Win7, there are 2 issues.
1. He gets a warning that the 1_setup.exe has failed when installing USER_setup.exe. I asked him to try to install the 1_setup.exe directly, independent of the USER_setup.exe. It worked perfectly. Since we've been having issues with the server at work and download speeds, I am quick to attribute the failure via USER_setup.exe to timed-out download speeds. Assuming I'm wrong, which is highly likely, what else could be causing this?
2. He gets a Custom Setup screen with an empty box (where normally would show features or components that are being installed). I am unsure why this is happening because when I thought that the custom setup screen is only supposed to appear if at least one feature has Display = "Visible", but I've checked every single feature in this project and the Display is set to "Not Visible" on all of them.
Thanks for any and all of your advice!