You can install the official Adobe Reader in Ubuntu 9.10 (Karmic Koala).
Download .deb package from here called Linux- x86 (.deb)
The download weighs in at a heavy 60.5 MB
The system requirements are:
- 32-bit Intel Pentium processor or equivalent
- LSB (Linux Standard Base) 3.1 compliant systems including Red Hat® Linux WS 5, SUSE® Linux Enterprise Desktop (SLED) 10, and Ubuntu 6.10
- GNOME or KDE Desktop Environment
- 512MB of RAM (1GB recommended)
- 125MB of available hard-disk space (additional 75MB required for all supported font packs)
- GTK+ (GIMP Toolkit) user interface library, version 2.6 or later
- Firefox 1.5 or later, Mozilla 1.7.3 or later
