[development] Question on base_path() in hook_init and caching

[David Metzler]

I've been recently struggling with getting my cas module to support  
caching (not agressive caching).  I started by getting error messages  
when I called arg() in my hook_init and am now having problems with  
base_path() not being defined.

Can anyone suggest a strategy for eliminating these errors?  Is there  
a bootstrap function I should be calling in my hook_init?

If not should I be filing a core bug related to this, or should I not  
be able to use arg and base_path in a hook_init function?

Thanks for any help

Dave