Silvia: What kind of problem do you have?
As described in the original post but let me describe what I have learned since then. I noticed that another person mentioned this problem in July 2006; I am the original poster.
I currently use ver 3.92 (Build 330) as of August 2006 (currently the latest).
I name saved sessions based on the server they connect to and which set of files (locally) they are associated with. There are times when I have decided to rename a session but had a failure. I found the problem is actually an issue with updating the WinSCP3.ini file in general when there are a lot of entries already in it. I have 65 sessions saved. If I try to add one, I get the error, "Unable to update C:\Program Files\WinSCP\WinSCP3.ini"
If I delete some entries, then I can add a new session. Sometimes deleting one entry is not enough so the problem may be size related. The problem seems to lie in the limit to the number of sessions that can be saved in WinSCP3.ini or its total size. My WinSCP3.ini file is around 65k, which implies to me that about 1k is used per entry. Is it the total size or the number of entries? Either way, if you could allow more sessions to be saved, then I can again test the rename issue. The problem might be solved then. This may cure other issues that are session related. I have noticed that this size/number entries problem has not been mentioned so I expect that most people do not have as many session entries as I have.
I do know that the part where a new session is added but had a failure, then another attempt shows that the session already exists is still there when it should not be obviously. That issue could be that the session list is not refreshed, or some variable has been set to indicate a session exists after adding when in fact, it never actually got added.