This type of issue is generally not a Crystal problem, but a configuration issue on the workstation where the software is being installed.
What type of data connection are you using? If it's ODBC, is the same ODBC connection set up on the client computer? If it's a Client/Server database (MS SQL Server, Oracle, etc.) is the database client software installed on the client computer? If it's not Client/Server, does the user have access to the folder where the database is located?
-Dell