In Islam it is prohobited to link our prophet Muhammed to any good things that happen to us.
Muhammed is a messenger who delivered his message.
Any good thing should be linked to God blessing and God Mercy.
In Islam Shirk is the biggest sin and here is useful link
for the definition of Shirk
http://ask.reference.com/related/Why+Is+Shirk+the+Major+Sin+of+Islam?qsr...