after the reboot and the manager can't find the client, i know the client is working. i reinstalled the manager and see tasks that have been working. in theory, i don't need the manager, but it's awkward to not see what is going on.
also, i just noticed an interesting detail that i missed before. when i try to install 7.0.28, 7.0.27 gets installed. i manually type the commands, so i know i typed the correct 7.0.28 version. i searched the BOINC forums and i am not the only person with this problem. unfortunately, no fix was provided. so, maybe when i thought i installed the BOINC 7.0.28 64-bit version, Kubuntu overrode my commands and installed the 7.0.27 32-bit version that came with Kubuntu. weird.
maybe i'll test a live DVD of Linux Mint KDE. or just Kubuntu 32-bit.