Unable to launch assistant, because libjpeg.so.62 is missing.

This seems to be a new error. I didn't have that problem on the very same machine with Beta2

See:
/home/holger/Betas/Qt5.0.0-rc1/5.0.0-rc1/gcc_64/bin/assistant: error while loading shared libraries: libjpeg.so.62: cannot open shared object file: No such file or directory

QtCreator also shows that it could not load the Help plugin.

Although this can be solved by simply installing the libjpeg.so.62 from apt, I think that this is a regression because it used to work fine on beta2