How to view databases and tables after 'imp' import using Oracle SQL developer
SQL Developer shows you the objects of the user you connect as.  It looks like you are connected as SYS or other high privilege user.  Way, way at the bottom of the file tree on the left is the "Other Users" icon.

Click on this and all the database users  (or schemas) will be shown. If "meltshop" is a user they will be listed there.

Now that you have provided more details I see that the user name is ML2_RT. This schema has been imported into the SYSTEM user which is unfortunate as this should not be used for user data. You should try this which points the data to a user

CREATE USER ML2_RT identified by "aPassword" DEFAULT TABLESPACE USERS;
GRANT CONNECT, unlimited tablespace TO ML2_RT;
then reimport again

imp database name/password@XE file=&lt;your file path and dump file name&gt;  
  fromuser=ML2_RT touser=ML2_RT


Also you seem to have some errors with the character set due to the import having a different character set.  That will be harder to solve.