BOINC 7.0.24 and 7.0.25 have a bug that create a lot of exit code 1 and exit code 193 errors. That's probably where your "output file absent" errors come from. Why the package maintainers at Ubuntu went for release of a BROKEN BETA BOINC is beyond me (e.g. Berkeley official BOINC 7.0 release is 7.0.25), but since they don't want to burn themselves more, they were slow at releasing 7.0.27 which has everything fixed.

So you'll have to get this yourself:

For ubuntu 12.04, open a terminal and type each line as written, hitting "enter" after typing each line:

sudo apt-get remove boinc
sudo apt-get autoremove
sudo add-apt-repository ppa:pkg-boinc/ppa
sudo apt-get update
sudo apt-get install boinc

You can omit that last line "sudo apt-get install boinc", and instead open synaptic and choose boinc 7.0.27 there, and install.

With thanks to xclusive585 (Ex) for hunting that down and writing it up.