org.eclipse.swt.SWTError: XPCOM error

I was working in Eclipse Ganymede (on Ubuntu) when a error popped up after I dragged a window to another location. This actually happend because the JavaDoc window became active. As with most errors, I just ignored it. Oops. The next time I tried eclipse with the same workspace, it would not start.

The problem reported in the .metadate/.log file was:

org.eclipse.swt.SWTError: XPCOM error -2147467262
at org.eclipse.swt.browser.Mozilla.error(Mozilla.java:1638)
at org.eclipse.swt.browser.Mozilla.setText(Mozilla.java:1861)
at org.eclipse.swt.browser.Browser.setText(Browser.java:737)
at org.eclipse.jdt.internal.ui.infoviews.JavadocView.doSetInput(JavadocView.java:928)
at org.eclipse.jdt.internal.ui.infoviews.JavadocView.refresh(JavadocView.java:776)
at org.eclipse.jdt.internal.ui.infoviews.JavadocView.setBackground(JavadocView.java:763)

Quickly I entered it in Google and came to the answer.

1) sudo apt-get install xulrunner

2) Append the following line to your eclipse.ini file:
-Dorg.eclipse.swt.browser.XULRunnerPath=/usr/lib/xulrunner

Violla.

It worked.