000784 : Data can only be checked out from ArcSDE geodatabase release (1, 3, 0) or later.
Description
Creating checkouts is not supported in the release of the ArcSDE geodatabase you are connected to. This type of replication functionality is supported at ArcGIS 8.3 and beyond. If you receive this error, it means that a geodatabase you are connected to is from an earlier version.
Solution
You must use ArcSDE geodatabases with a minimum release version of 8.3.
7/10/2012