Sorry, I have no idea how the sudo thing works in Ubuntu. What I know is that "su" doesn't work.
So let me phrase it differently: Make sure that a line with the content "/usr/local/lib" exists in the file "/etc/ld.so.conf", if it doesn't, add it, and run the program "/sbin/ldconfig" after adding it. For how to get the required privileges, refer to the Ubuntu documentation.
Btw. this message
bash: /etc/ld.so.conf: No such file or directory
concerns me. Either Ubuntu has a different glibc configuration or you have a problem.