Oracle Message PLS-00378 - invalid compilation unit for this release of PL/SQL

ERRORinvalid compilation unit for this release of PL/SQL
CAUSEA compilation unit is a file containing PL/SQL source code that is passed to the compiler. Only compilation units containing blocks, declarations, statements, and subprograms are allowed. This error occurs when some other language construct is passed to the compiler.
ACTIONMake sure the compilation unit contains only blocks, declarations, statements, and subprograms.