This problem has been fixed in Firefox 5. You can install it by going to firefox.com/m and selecting the beta download link.
SwiftKey is a popular software keyboard for Android devices. There is a known problem that causes it to crash when used with Firefox. We are working to get this fixed, but until then the solution is to temporarily disable SwiftKey.
This article only applies to Android devices
How do I disable SwiftKey?
- Open the Android Settings app.
- Select Language & keyboard.
- Tap the checkbox next to SwiftKey to disable it.
This problem has been fixed as of Firefox 5.