Thanks! That worked! But at first I found it a little confusing to tell which ones were the optional steps .
Open Control panel
Open Administrative tools
Open Microsoft .NET Framework 1.1 Configuration
In the tree on the left expand Runtime Security Policy
Choose Machine
Choose Code Groups\All Code\
Select the zone from which you are running your application, e.g. Intranet
or Internet (look the IE status bar icons to know which zone to choose)
you can either change the settings for the zone (all .NET components
running in it) or ...
Right click the zone and choose duplicate
Rename the copy to fc.net or something similar
Open the copy properties dialog, go to the Membership conditions tab
For condition choose 'strong name' and import the flowchart.net.dll
assembly
Go to the Permission Set tab and choose 'Everything'
choose ok etc. until the settings are applied
restart all IE instances and reload the application.
But that must be done on each client PC.
Stoyan