Symptoms
In the Configure Publishing and Distribution Wizard, if you select the option to customize the settings rather than accept the default values, you are given the opportunity to change the distribution database name from its default of “distribution.” Although you cannot type a space character in the Distribution Database Name box, it does accept a space character if you copy a text string (for example, “my database”) to the clipboard and paste it in.
If the name you use contains a space character, the database is still created. However, if the name that you paste in begins with a space character (for example, ” my database”), the wizard fails with the following error message:

SQL Server Enterprise Manager could not configure ’server_name’ as the distributor for ’server_name’.
Error 14262: The specified @database_name (‘db_name’) does not exist.
Resolution
To work around this problem:do not use spaces in the name
-or-
make sure that the database name you are pasting in does not contain a leading space character.