There could be difference in declarations based on the OS. But solution is fairly simple, you can simply add multi-tags for the components that are recorded differently in different OSs. Check out Silk help in declaring multi-tags with different GUITYPE, also check out different GUI Specifiers that you can use for different OSs. This should solve your problem.
Declare SwfTextField Password like this:
</font><blockquote><font size="1" face="Verdana, Arial, Helvetica">code:</font><hr /><pre style="font-size:x-small; font-family: monospace;">SwfTextField Password
mswxp multitag "Password:"
msw2000 multitag "[WindowsForms10.STATIC.app1d]Password:"
"[WindowsForms10.STATIC.app1d]$66256"</pre><hr /></blockquote><font size="2" face="Verdana, Arial, Helvetica">You should be able to identify the Text Field as SwfTextField in both OS.
Make sure you have enabled the correct set of extensions on both machines. you can save the options set on the Win XP machine and use the same for Win2k.
From your declaration it looks like on XP you have some extension enabled, whihc enables silk to recognize a particular class, while the same class on W2k is not be recognized, marking it as CustomWin.