Samba question

I had troubles getting Samba to map to a Win98 share.

The command I used was:

[root@devlap1 /root]# mount -t smbfs -o username=rgc //192.168.1.200/downloads /mnt/bobpc
session request to 192.168.1.200 failed
session request to *SMBSERVER failed
SMB connection failed

Then I used:
[root@devlap1 /root]# mount -t smbfs -o username=rgc //cx267762-k/download /mnt/bobpc

and it worked.

My question is:
Why didn't the IP address work, while the netbios name did? I can connect from other win machines using the IP address instead of the netbios name.

Second question:
If I want to mount this share automatically, can I put it it /etc/fstab?

Thanks for any insight.
Bob