You are trying to share a map package that is referencing the original data source instead of copying the data along with the package, and your map document is currently set to use relative paths for data sources.
- Set map document to use absolute paths for data sources in the Map Document Properties dialog box.
- Alternatively, uncheck the Reference all data check box in the Map Package dialog box.
When you share a package with others, it is important to ensure that other users of the package have access to the data source being referred to in the map document. You can assure this in two ways—one is to package the data with the map document, and if this not possible for some reason (for example, large data), ensure that the data source is accessible to the users you share with, and you create the package with Reference all data check box checked. When you use the second sharing method, be sure to set your map document to use absolute paths for data source (that is, uncheck Store relative paths for data sources).