In NetBeans 6.9 the Hudson plugin is unable to perform access-controlled operations (depending on configuration, this might include starting a job) when you enable protection against "cross-site request forgery". Bug #193008 is fixed in 7.0; for users of earlier IDEs, the workaround is to disable CSRF crumbs in Hudson security settings.
In an account with administrative privileges log in to Hudson and:
- Click "Manage Hudson"
- Click "Configure Hudson"
- Make sure that the "Prevent Cross Site Request Forgery exploits" checkbox is disabled
- Save changes
If that does not fix the problem, there may be some other bug. Check bug #193066 for example. Feel free to file a new bug under connecteddeveloper/Hudson but you are most likely to get a response if you can attach complete instructions to reproduce the bug, including server setup. Adding -J-Dorg.netbeans.modules.hudson.level=FINER to netbeans.conf will also produce helpful diagnostics in your log file.