This happens to me too. For now I just stand on top of my quarry and go make myself a sandwich
Get MCedit, or any other world editor.
Since it's by default set up for normal minecraft, I copied my world in the minecraft folder and opened MCedit to remove the pipe (I hope you remember where it is, should be close to steve).
I then simply put the corrected version back into the technic pack folder and voila!
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Launcher/pack Version: 0.5.4.9
Operating System: Mac OS X 10.7.3
Version of Java: Java for OS X 2012-001 (1.6.0_31)
Description of Problem:
Placing any kind of pipe in the world crashes the game. 'Saving chances' message, white screen. Need to force quit. World is not usable anymore. I used MCedit to remove the block, and this fixed the issue.
I then zipped up my save file and did a few more tests (all I had to do was delete and unzip). To make sure. Downloaded new launcher (the one that works offline too), redownloaded entire pack.
First line of stack trace in log file
"java.lang.NoSuchMethodError: buildcraft.api.Orientations.dirs()[Lbuildcraft/api/Orientations"
Error Messages: n/a
Link to pastebin of log: http://pastebin.com/Medbyd0P