Unexpected Reset

[netstranger.nz]

Hi Everyone,
I am PIC hobbyist. Working through different projects I noticed that the most difficult problem to solve is unexpected PIC reset. I browsed the forum and found that people had similar problems. Here are some links:
http://www.picbasic.co.uk/forum/showthread.php?t=7926
http://www.picbasic.co.uk/forum/showthread.php?t=5650
There was another one where the guy was designing ignition coil driver but I could not find the thread.
I came across the project where PIC resets quite regularly and I am not able to fix it. Attached files are the circuitry and the code.

MCLR is configured as an input. Pic runs of internal Oscillator
PIC resets almost every time when you press the button. Debugging “S” indicates it. It could be any PIC providing MCLR is cofigured as an input.
Any help is appreciated. If you came across similar problem in the past can you please share your experience.
I would like to thank all the helpers on this forum and give my best regards to DarrelTaylor for his Basic Extensions and all the posts.