If you install a fixpack or a hotfix for a domino server running on Linux/Unix you might see the following message:

You must create the environment variable NUI_NOTESDIR as path of the directory
that contains notes/latest. E.g., for the default path /opt/lotus/notes/latest
NUI_NOTESDIR=/opt/lotus
export NUI_NOTESDIR

To fix this issue on a domino server running on Debian (yes unsupported ;-) ) you could for example edit the:

/etc/profile

via "nano /etc/profile"

and add the line:

export NUI_NOTESDIR=<path_to_lotus>

where <path_to_lotus> is the full path to the 'lotus' directory for the server to receive the hotfix installation

for example

export NUI_NOTESDIR=/opt/ibm/lotus

After that relogin and the issue is solved.