SSL problem: session drops

Hi everybody,
We have a problem with webMethods Integration Server 4.6, used as web server on HTTPS port (SSL with Verisign certificate).
When connected with MSIE 5.5 (SP2), if we try to navigate from one page to another, when the connection status is “CLOSE-WAIT” (from netstat command on WinNT), the browser displays a “cannot display page” message, and the session expires.
The weird thing is that if, instead, the session expires by timeout by itself, when we click on any link to other pages, the session is being restored, and all is OK!
It seems that this issue happens only when the status is CLOSE-WAIT, and only with IE (Netscape works fine, but our site was developed for IE).
Any help will be appreciate, thanks!