[imp] imp page cannot be displayed error in IE

[David Bain]

I'm using Debian Sarge,
 Apache/2.0.54/PHP/4.3.10-16 mod_ssl/2.0.54 OpenSSL/0.9.7e mod_perl/1.999.21
Perl/v5.8.4

With IMP 4.0.2-2

The mail is accessed only via https

When using internet explorer, I will occassionaly see this page cannot be
displayed. I've searched mailing lists and I don't see a definitive solution
to this.

Does anyone know a solution?