Getting error while reading data from a file using UTL_FILE

Hi Experts,
Need your help. I am using Oracle 10g database. I have developed a script in which I have used UTL_FILE api to read data from a file. While running the script I am getting error like identifier 'UTL_FILE' must be declared. I am sure the directory "fileout" and file "MYFILE" is present in the database. Please let me know the reason for this error and how to resolve this issue. Here I've attached the screen shot of the error.
Error:
ERROR at line 3: ORA-06550: line 3, column 6: PLS-00201: identifier 'UTL_FILE' must be declared ORA-06550: line 3, column 6:
