ORA-06508 PL/SQL: could not find program unit being called

[meteo1974]

technical environment : Forms [32 Bit] Version 9.0.2.9.0 (Production), oracle JInitiator: Version
1.3.1.9, WebUtil Version 1.0.2(Beta), window xp service pack 2 build 2600, Internet Explorer 8

I created a form called read_web_file.fmb

this form has
a- block called METAR_BLOCK under which a text item called metar_code with initial values airport code (OLBA, LCLK )

b- block called Button under which a button PASS_VAUES is created and a procedure p993_GET_Qry_To_avia_weather has been called


After executing the following procedure an error is happened: ORA-06508 PL/SQL: could not find program unit being called.

PROCEDURE p993_GET_Qry_To_avia_weather
IS
    l_http_request   UTL_HTTP.req;
    l_http_response  UTL_HTTP.resp;
    l_buffer_size    NUMBER(10) := 512;
    l_line_size      NUMBER(10) := 70;
    l_lines_count    NUMBER(10) := 10;
    l_string_request VARCHAR2(512);
    l_url            VARCHAR2(512);
    l_line           VARCHAR2(128);
    l_raw_data       RAW(512);
    l_clob_response  CLOB;
 
BEGIN     
    /*
       send HTTP request depending on the html file structure fount at the url : http:/aviationweather.gov/adds/metars/  :
                                                       ...
                   < FORM name="textForm" method="GET" action="">  
                   <INPUT SIZE=14 NAME="station_ids" TYPE="text">
                                        ............
                <INPUT NAME="submitmet" TYPE="submit" VALUE="Submit">
                 <INPUT TYPE="reset" VALUE="Reset FORM"></FORM>
                                             .......              ...
    */   
    l_url := 'http://aviationweather.gov/adds/metars?station_ids='||:METAR_BLOCK.metars;  
    l_http_request := UTL_HTTP.begin_request(url =>l_url ,method => 'GET');    
    UTL_HTTP.set_header(r => l_http_request, name => 'User-Agent', value => 'IE8');
    UTL_HTTP.set_header(l_http_request, 'Host', 'aviationweather.gov');
 
    l_http_response := UTL_HTTP.get_response(l_http_request);
    DBMS_OUTPUT.put_line('Response> status_code: "' || l_http_response.status_code || '"');
    DBMS_OUTPUT.put_line('Response> reason_phrase: "' ||l_http_response.reason_phrase || '"');
    DBMS_OUTPUT.put_line('Response> http_version: "' ||l_http_response.http_version || '"');
 
       BEGIN  -- response block
 
         <<response_loop>>
             LOOP
                 UTL_HTTP.read_raw(l_http_response, l_raw_data, l_buffer_size);
                 l_clob_response := l_clob_response || UTL_RAW.cast_to_varchar2(l_raw_data);
             END LOOP response_loop;
 
             EXCEPTION
                 WHEN UTL_HTTP.end_of_body THEN
                     UTL_HTTP.end_response(l_http_response);
       END;    -- Response Block
 
    DBMS_OUTPUT.put_line('Response> length: "' || LENGTH(l_clob_response) || '"');
    DBMS_OUTPUT.put_line(CHR(10) || '=== Print first ' || l_lines_count || ' lines of HTTP response... ===' || CHR(10) || CHR(10));
 
          <<print_response>>
           FOR i IN 0..CEIL(LENGTH(l_clob_response) / l_line_size) - 1 LOOP
               l_line := SUBSTR(l_clob_response, i * l_line_size + 1, l_line_size);
               DBMS_OUTPUT.put_line('[' || LPAD(i, 2, '0') || ']: ' || SUBSTR(TRIM(l_line),1,50) || '...');
               EXIT WHEN i > l_lines_count - 1;
           END LOOP print_response;
 
           IF l_http_request.private_hndl IS NOT NULL THEN
               UTL_HTTP.end_request(l_http_request);
           END IF;
 
           IF l_http_response.private_hndl IS NOT NULL THEN
               UTL_HTTP.end_response(l_http_response);
           END IF;

I run my form in debug mode when the cursor arrive on the instruction: l_http_request := UTL_HTTP.begin_request(url =>l_url ,method => 'GET' ) or in any instruction which invoke a procedure or function in the package UTL_HTTP body i have got the mentioned error .
I would like to clarify that UTL_HTTP specification is opened and compiled under the Program Unit in the object navigator .

any one Can help me how I can using and wrap oracle supplied packages (just as utl_url or utl_http) through my own stored procedures and call them from my forms??

Thank you and i appreciate any support.

[gaurishere]

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