Cause: An invalid package specification
or stored subprogram was referenced. A package specification or stored
subprogram is invalid if its source code or any database object it references
has been DROPped, REPLACEd, or ALTERed since it was last compiled.
Action: Find out what invalidated the
package specification or stored subprogram, then make sure that Oracle can
recompile it without errors.

Relared Errors:
PLS-00906:
Compilation is not possible
PLS-00907:
cannot load library unit string (referenced by
string)
PLS-00908: The
stored format of string is not supported by this
release
PLS-00909:
object string is not declared or insufficient privileges to access
object
PLS-00910:
insufficient privilege to inherit from type string
PLS-00920:
parameter plsql_native_library_dir is not set
PLS-00923:
native compilation failed: string:string
PLS-00924:
native compilation is not supported on this platform
PLS-00925:
native compilation failed: Unable to create C file (string
string
PLS-00950: In
this version, PL/SQL tables can not be used in this SQL
statement.