Can't connect (MAP) to a share on XP from Windows 8.1

I get an invalid password error message when I try to make a network connection to a share on a Windows XP machine from a Windows 8.1 machine. I know that this has worked before as recently as a month ago. I have a Windows NT shell script that I have used for doing backups from PC to PC that I have used for years. I wrote it myself when I used to do that kind of thing on a regular basis. And I know that I have used it successfully between these 2 machines within the last month. I haven't been doing much network stuff for years that I used to do on a regular basis when I was working as a programmer that knew enough about Windows networking to be better than just dangerous.

Please see attached screen shot. It shows the domain that I am being authenticated by as HP003. That is the machine that I am logged on to right now. I haven't joined that machine to a domain just because I don't want to for now. So when I logon to that machine it is always with a local UID and PW. And it always works including when that machine times out and I have to press ctl-alt-del to get back in. I thought I remembered that is the credentials that I use to map a drive letter on HP003 to a share on IBM003. But for some reason now it won't work. What the hell am I doing wrong?

Thank you for any help you can provide me.