This one depends on the the setup and it is not guaranteed that this solution will work in all cases (for example, this could be a general issue if your datasource is just too big and slow to retrieve), but in any case, please check out the following forum threads for suggestions, hotfix information and leads:

http://forums.labs.infragistics.com/forums/p/8970/35052.aspx

http://forums.infragistics.com/forums/t/12711.aspx

The forum thread above can certainly provide additional clues.