Regarding your first issue:
"When I create a new appointment, the appointment is created several
hours later. For example, if I set the appointment on 3:00-4:00, it will
be created on 11:00-12:00"
This could be caused if your client machine is in a different time zone from your server.
You should refer to the Handling Time Zones
documentation page and the /Time Zones"
demo at http://demos.telerik.com/aspnet-ajax/scheduler/examples/timezones/defaultcs.aspx
for insights on working with the TimeZoneOffset property (a TimeSpan indicating the difference (offset) between internal (UTC) and display time).
Also, regarding your issue:
3a: "There's a "!" image on the right upper corner of the subject
This is standard behavior and can be reproduced with the online / First Look"
demo at http://demos.telerik.com/aspnet-ajax/scheduler/examples/outlook2007/defaultcs.aspx
. There's an alert icon added when the subject line is empty and it disappears once text is added to the subject.
Hope this is helpful!