Problem compiling view when it is referencing a table in an other view: insufficient privileges
Even though you are using SYS (which you really shouldn't be), the view is stored in a SCHEMA1, as I will refer to it.  SCHEMA1 is trying to select from a table, via the view, in SCHEMA2.  Therefore, you need to grant SELECT access to SCHEMA2.TABLE to SCHEMA1.

And don't run things as SYS. :)