Hi Polter,
it seems that BSM 9.26 is much more sensitive to the browser type and version than earlier BSM versions.
I've seen this issue when trying to create a profile database and others.
If not done already, try Mozilla FF or a newer version of IE, or run IE in compatibility mode.
If it's really urgent that you can change the settings right now, have a look at KCS document
KM01296247 - BSM - changing InfraStructure Settings via JMX
Greetings
Siggi