If you need to run native Linux client for Lotus Notes 8.5 on Ubuntu 10.04:

1) After installing your ibm_lotus_notes*.deb files, drop the following files under /opt/ibm/lotus/notes

libgdk-x11-2.0.so.0
libgtk-x11-2.0.so.0
libgdk_pixbuf_xlib-2.0.so.0
libgdk_pixbuf-2.0.so.0

You can get the files here.

2) Install msttcorefonts package: sudo apt-get install msttcorefonts

3) Go to File -> Preferences and choose Windows and Themes on the left pane. For Theme, choose Operating System Theme. This way most of the fonts in the UI look much better.