Please note that, at present, the String library has bugs as discussed here and here.
In particular, the dynamic memory allocation used by the String class may fail and cause random crashes.
I recommend reworking your code to manage without String. Use C-style strings instead (strcpy, strcat, strcmp, etc.).
Alternatively, install the fix described here:
http://arduino.cc/forum/index.php/topic,145765
all of my code can not be posted because it is above the maximum allowed characters for a post.
You can do attachments.