internet connection sharing timeout and LAn problem

First Problem:

I have a Win 98 PC connected to a Win XP PC. The Win 98 PC
can "see" the shared directories on the XP PC but when I
try to access the workgroup MSHOME on the XP PC, I get the
message that I do not have permission to use the
resources. In effect, I have a one way LAN.

Second Problem:
After booting the Win 98 PC, I can access the internet via
the gateway through the XP PC for what appears to be
exactly 10 minutes. Then the gateway is closed and I have
to reboot the 98 PC to re-access the Internet. However,
there is no timeout with MSN Messenger on the 98 PC. MSN
messenger can be used endlessly to chat from the 98 PC via
the XP PC. This I do not get (browser connection drops
after 10 minutes, Messenger connection stays). I have
tried every conceivable thing (including such things as
editing registry parameters) but without success.

So, I need answers to two questions:

Question 1: Why does the Win 98 PC see the resources on
the Win XP PC but not the reverse?

Question 2: Why does the internet connection gateway drop
after 10 minutes for my browsers (both IE6 and Opera 7)
but MSN keeps on trucking along via the gateway?