I have recently helped my son install Tekkit to work with Minecraft and along the way I encountered issues with both the Java version and with the launcher itself.
The symptoms of the launcher failing include the Tekkit Launcher freezing at the splash screen and after getting past this issue failing to log in to Minecraft.
Here is how I resolved the problem:
- Install Java from the Oracle site (http://www.oracle.com/technetwork/java/javase/downloads/jre-6u26-download-400751.html)
- Select the runtime for your system.
- Download the Tekkit launcher (http://www.technicpack.net/tekkit/). On the right hand side of the web page there are two download links. Click the link that says "Download the Technic Launcher".
- Running the launcher might come up with a "Cannot find java error". To run the launcher click start and type %appdata% (from windows, not tried in Linux).
- From within the roaming folder find the tekkit launcher folder and right click Tekkit Launcher and choose open with Java.
- If you get the splash screen and nothing else (because you have Zonealarm as your firewall), open Zonealarm and click on the icon for computer settings. Now click the link to view blocked requests.
- In the blocked requests click clear.
- Now run the launcher again and then click refresh in zonealarm. A new line should have appeared.
- Click the link and click to add to the trusted zone.
- Now run the Tekkit Launcher again and this time you should see the application load.
- When you try to connect to Minecraft it might fail. If it does it is because Zonealarm is blocking another ip address. Go the list of blocked requests and refresh the list. Add the latest one to the trusted sites.
- Run the launcher again and log in to Minecraft and it should now work.