For you to make the Transportable tablespace

First you have identify the tablespace whether it is self contained.

To say self-contained means say if there is only one table in a tablespace and for that if index is there on the other tablespace.You have to do a transporatble tablespace both for the data and index tablespace

you can check by

1Checking if a transportable tablespace set is self-contained

execute DBMS_TTS.TRANSPORT_SET_CHECK('AGG_DATA,AGG_INDEXES','True');

For your case pls check the file permissions and whether you do have rights to copy the files.