Steps to reproduce:
1) Add maven 2 installation named e.g. "Maven 2.2.1"
2) Create a maven 2 build job for a correct maven 2 project, and make use of maven 2 installed in step 1
3) Run build from step 2, and it is successful
4) Manage hudson, and rename maven 2 installation to e.g. "Apache Maven 2.2.1"
5) Run the same build from step 2, and it fails with following error message:

"ERROR: A Maven installation needs to be available for this project to be built.
Either your server has no Maven installations defined, or the requested Maven version does not exist."

It seems that some references do not get updated when maven installation is renamed.

Workaround is to change job's maven to another installation, save the change, and then edit job again reverting the change and save it again - after this job runs same as before installation was renamed.