This plugin requires special hudson setup to work.

1. Skype must be running as the same user as the hudson server
2. If running hudson on a 64bit JDK you must add a windows/linux slave running on a 32bit jdk
3. The slave must have a "skype" label
4. Check the logs to see if it connects ok to skype
5. If it connects ok, then you must allow the java plugin to connect with skype
6. Add skypeid to all users in hudson
7. Good luck

Notes
The libskype.so is build for CentOS 5.5
I used the static version of skype, but I guess other versions will work also.