Comment 8 for bug 38270

Also, this appears to happen most when installing mono-common_1.9.1+dfsg-4ubuntu2_i386.deb:

Recommended packages:
  binfmt-support
The following NEW packages will be installed:
  mono-common
0 upgraded, 1 newly installed, 0 to remove and 13 not upgraded.
Need to get 0B/118kB of archives.
After this operation, 758kB of additional disk space will be used.
Selecting previously deselected package mono-common.
(Reading database ... 234411 files and directories currently installed.)
Unpacking mono-common (from .../mono-common_1.9.1+dfsg-4ubuntu2_i386.deb) ...
Processing triggers for man-db ...
Setting up mono-common (1.9.1+dfsg-4ubuntu2) ...
update-binfmts: warning: /usr/share/binfmts/cli: no executable /usr/bin/cli
found, but continuing anyway as you request

I'm using Ubuntu 8.10.