I am downloading Oracle 8.1.7 now ... :( sloooooow ...
The problem I had was exporting from Oracle 8.1.6 on Solaris and trying to import on 8.1.7 on Linux ... so I will do a complete backup of my 8.1.6, install a fresh Oracle 8.1.7 on Solaris and try to import the exported file from 8.1.6 ...
If that doesn't work, I will try to do the "migration from 8.1.6 to 8.1.7" .. but everything I read about it shows me that it's not as simple as the export/import :)