This is a error that some devices/roms have had.
You will need to edit the boot script, open the boot script (found at data/data/com.zpwebsites.linuxonandroid/files) using a text editor (on windows use notepad++) and find the section which says it is checking for su rights. Delete this section or comment it out from the script, save it and re run. You may get more errors in which case its likely your rom is not compatible with the project, or for many it simply fixes the problem and boots fine.
This error pops up in Arm v6 Devices when you try to install Backtrack 9 and Ubuntu 12.04.
It is caused from the current precompiled builds (Ubuntu 12.04 and Backtrack 9) being made for Arm v7 Architecture.
Until another is made with arm v6 support you're going to have to use the Debian build or a custom build.