[ic] Constant "Undefined catalog" error

[Nick]

Currently running Interchange 4.8.6

I have installed Interchange 4.8.6 (with a host), which was just 
before the 4.8.7 release.  I am currently in beta test mode before I 
go live with the real store.  Somehow, I seem to keep receiving this 
error message when I access the store:
Undefined catalog: /~applebit/cgi-bin/cart.cgi

I then have to log a request or a ticket to restart the Interchange 
server to get my store back up and running.  This is then manually 
executed by the host from within 10 minutes and up to 7 hours.  My 
host ensures me that it is compatible with CPanel X.

I am just trying to fix a better solution this ongoing problem.  In 
the space of a week, I received this error message 4 times for no 
apparent reason, or no major work on my website.  Luckily for me, mu 
store is in test mode and not live.  Unfortunately, I cannot have 
this ongoing problem if my store is live ie; the store is down by up 
to 7 hours.

My easy enough questions are:
1) What causes this problem?
2) Should I upgrade to the latest 4.9.8 which is still a beta 
version?  I read that many people are on this version, so it can't be 
that bad, but will it fix or at least adhere to this problem?  I 
would like to update regardless, as I like the features in 4.9.x over 
4.8.x...
3) If the host is the problem, can someone indicate a host that will 
guarantee that this problem will not arise?

Any suggestions appreciated!  I am sure someone can shed some light 
on my basic questions, as I believe that Interchange is a great 
product, but not when it goes down automatically.

Thanks
Nick