Whenever a client tries to write their roaming profile back to the server on logout, the Windows XP (SP2) client gives an invalid network name, and thus can't write back their profile.
However, if you put the debug level of smbd towards a high level (we tried with 32) it does work. It seems somebody also had this issue back in July 2001. I can reproduce this issue.
Workaround: debug level towards 32 :)
Created attachment 2199 [details]
This is the configuration we have been using (mind the debug level = 32, if this is used the problem will not exist!)
It seems that the current version we are using (3.0.30) isn't experiencing this anymore! Problem fixed :)