The difference is that the bundle includes all the other packages that the mains package expects to be present because it is dependant on them. So if you loaded a screensaver plugin screensaver-7Seg_1.0.0_mipsel.opk it would also include the main screensaver program screensaver_0.2_mipsel.opk as well. If you could send a the error message it should be possible to see what's happening, I guess the bundle installer is trying to install a package the is not bundled, but that may already be present on your Humax from a previous installation