It appears that your Excel file contains variables names that are not in standard SAS format (i.e. some may contain a blank space).
By default, Enterprise Guide executes the statement "options validvarname=any;".
This setting of the VALIDVARNAME system option allows the use of column
names that contain embedded spaces and special characters.
For more information please refer to:
http://support.sas.com/kb/14/661.html
I would suggest to remove these blanks before importing the Excel file.
Hope this helps,
Udo