Verify that the source and target data directories are defined.
Verify that the source and target data directories are defined.

Some formatting.

at7/ensembl,james-monkeyshines/ensembl,mjg17/ensembl,james-monkeyshines/ensembl,Ensembl/ensembl,mjg17/ensembl,mjg17/ensembl,james-monkeyshines/ensembl,Ensembl/ensembl,Ensembl/ensembl,danstaines/ensembl,willmclaren/ensembl,danstaines/ensembl,willmclaren/ensembl,muffato/ensembl,at7/ensembl,muffato/ensembl,muffato/ensembl,danstaines/ensembl,muffato/ensembl,mjg17/ensembl,at7/ensembl,at7/ensembl,james-monkeyshines/ensembl,Ensembl/ensembl