Infinite loops !

[René Micout]

Hello from Paris,
I have a question about infinite loops.
I make a musical arpeggiator (a virtual replica Reactogon see video :  
http://technabob.com/blog/2007/09/08/reactogon-interactive-sequencer- 
reminds-me-of-star-trek/), the work is progressing but I have 2  
encountering problems: 1 / When I start an endless loop (it is the  
goal of the program, I stop it by pressing a key) it stop after few  
time with the following message: "Handler: can't find handler" while  
it worked for 150 or 200 times...
2 / It is not possible to intervene at any time in the running of the  
program to change certain provisions
Thanks for any ideas and your indulgence for my english
René