Don't people bother to search for themselves? 30 seconds gets me these:
http://www.diynot.com/diy/threads/help-vokera-linea-24-code-07.40873/
http://howtomendit.com/answers.php?id=193013
code 07 means the primary thermister is open circuit, it is not able to sense the resistance through it, it is located on the right hand side of the main heat exchanger with two brown wires going to it, should have a resistance of around 12kOhms at room temp(20 degs) needs to be drained down to be replaced, hope this helps
XXX
December 2015