Hi Srini,
it seems for me that your code may trigger the redirect from "/" to "/MicroStrategy/servlet/mstrWeb" and outputs the maintenance page on a single HTTP request. This will lead to "Multiple redirect/respond invocations" and raises an error.
Take a look into you LTM log and keep an eye on "Multiple redirect/respond invocations..." messages. If this is your problem, than make sure that the first iRule informs the second iRule that the given request is already responded. Alternativly put the code into y single iRule and "return" the processing after each individual response.
Cheers, Kai