Question about Outlook Express

When I am preparing an email message, to which I plan to attach a file that is stored on my hard drive (in My Docs for example), I find that if go to or have previously gone to the FOLDER first (during the email session - but before attempting to attach the doc/file) to preview the file/doc, when I return to the email message and attempt to attach the doc/file, the FOLDER is no longer listed among the items in My Docs.  I can see other FOLDERS that are still listed in My Docs.  However, I also cannot find other FOLDERS which 'disappeared' when I've tried to attach docs from FOLDERS during various other emails that I've previously composed.  However, If / when I go out of email and go directly to my library and open My Docs, ALL of the FOLDERs are still listed.  But when I return to the email message and attempt to find the folder & attach docs, the folder is not listed !??  So therefore, because I cannot find the folder, I cannot access any docs/files within the folder.  

In order to get around this, I have to 1) come back out of Outlook, 2) go directly to my library & My Docs, 3) open the FOLDER, 3) copy and paste the doc/file that I want to attach, so that it is listed as a single file/doc (not contained within a FOLDER), 4) go back to the email and then access and attach the file/doc from My Docs.  I DID NOT EXPERIENCE THIS PROBLEM BEFORE THE RECENT HOTMAIL UPGRADE TO THE CURRENT OUTLOOK FORMAT.  I need help to understand why this is happening and where the folders are disappearing to and/or how do I access the folders directly through the Outlook attachment/insertion function.  

THANKS SO MUCH FOR YOU HELP :)