Not really related to the thread, you should have created a new one (after searching the forum for a previous similar question), anywho it's not related to the JB/exploit/HEN, it's what it says in the error message your HD lacks 20 GB of contiguous space the free space is probably fragmented and Orbis requires contiguous sectors. The fastest workaround is deleting an installed title of at least 20 GB or more, another methods you find mentioned on the Interweb is forcing a DB rebuild from recovering mode, but watch out as you can also find people moaning online that a DB rebuild wiped all their installed FPKGs...
If you ask me, the foolproof way is to delete all the installed titles and install them from scratch...