Welcome to the OCPN forum! I'm afraid personally I can't help you, but I have a small tip: There are a few very skilled Apple users on this forum, but but the title of your post makes the probability that they will see it very small.
Try summing up the relevant information in your question in your title, this will increase your chances of getting help.
Instead of the meaningless "please help!", write something like "Newly installed OpenCPN
v3.0.2 crashes on Macbook Air with 10.7.4"