Message Oracle PCC-02303 - cannot open include file

ERRORcannot open include file
CAUSEThe precompiler was not able to open a header file specified using the #INCLUDE preprocessor directive or the EXEC SQL INCLUDE statement. This can happen if the file specification is inaccurate or if read permission or read-access rights on the file or on one or more of the directories in the path have not been granted.
ACTIONRecheck that the file specification is correct, that the file exists, and that read permission has been granted so that the file can be read.