Restoring DB for files...

Hi
In order to copy a database from a server to a server, I cant detach the database as there are many users connected to it. The transaction log is large file while the data is about 46 MB, I made a backup for the data file only, zipped it and copied it to the target server.
Ex: the name of the source DB on the source server is x, the file I took as a backup for is x-data
From the Enterprise Manager, right-click the x DB, All tasks, Backup database, in the backup option click the File and Filegroup option and chose the primary file group with x_data file.
Then, I created a new database name it y with y_data , y_log files on primary filegroup. I want to restore my backup to have the DB x on my target server,
I tried:
RESTORE DATABASE y
FILE = 'y_data',
FILEGROUP = 'primary'
FROM disk= 'E:\VMS\DBFiles\test'
GO

But it did not work. Any help?

Thanks,what is the error you are getting ?