Installation problem v. 1.40

Hi everybody
I've installed v 1.3 some time ago and everything worked like a charm from the start

not the same with v 1.4

I just set up up a new solution with all new files and changed the connectionstring in web.config to my previous one

default.aspx
error:
System.Runtime.InteropServices.ExternalException: Generic GDI+ error.

next I tryied to re-run install form start (in order to build a new database, even if there's no note about it in the install)

/install/install.aspx
error:
System.IndexOutOfRangeException: UnlimitedDownloads

what's the matter with this install?
stack details available on request

thanks for any useful suggestion

ok, here's the answer.
should you happen to be updating from a previous version do NOT modify new config file manually inserting your connectionstring: just leave it blank.

this way starting the website you'll be asked wheter you want to set up a new database or upgrade an existing one.
choose one.

this (and this only) is the correct upgrading procedure

You're right. Hope this screencast can help you