[c-nsp] Problems when configuring BGP on 4506

[Scott Granados]

I'm new with the 4506 so this may be an obvious problem.

In my case I have one 4506 that I'm using the layer 3 routing option.  I'm 
trying to send 1 full BGP feed for now for the purposes of testing, 
eventually I'll add another to make the excersize meaningful.  My problem is 
this, when I turn up the session after a few seconds up to a minute the 
routes withdraw and when I do a show ip BGP a.b.c.d I see the route entry 
and it's indicated to have no path available unaccessible.  When the routes 
first install they have the path available and work.  In parallel, I'm 
noticing a series of IP Cef Distributed errors concerning low memory.   (no 
bgp log messages)

So, am I seeing a limitation in the number of routes I can install?  The cpu 
shows 512 megs installed, is there a software limit that I'm bumping in to?

The switch is running 12.1-19 ?

Is this a hardware / memory issue or should I check in other areas?  What 
would make a bgp table full of routes remove once the table is downloaded?

Thank you
Scott

P.S.  Sorry if this is a n00by question, the 4506 is a new switch in my lab 
and google hasn't yielded me to many usable pointers yet.