Maybe this piece of code from series script explains a bit more?
   if (Pos('404 Not Found',Result)>0) then begin  //Banned IP. WEB_SPECIFIC.
        If BYPASS_SILENT Then ShowMessage('The URL is not in use (404 Not Found).'+Chr(13)+'Go to the provider web in order to in order to'+Chr(13)+'find the good page',SCRIPT_NAME);
        LogMessage(Chr(9)+Chr(9)+'      404 Not Found|');
        Result:=''; //Fatal error
    End;
   if (Pos('404 Error - IMDb',Result)>0) then begin  //Banned IP. WEB_SPECIFIC.
        If BYPASS_SILENT Then ShowMessage('The URL is not in use (404 Error - IMDb).'+Chr(13)+'Go to the provider web in order to in order to'+Chr(13)+'find the good page',SCRIPT_NAME);
        LogMessage(Chr(9)+Chr(9)+'      404 Error - IMDb|');
        Result:=''; //Fatal error
Thanks, afrocuban for this warning. 
 still have trouble with season trees in series:
When I run the new IMDB Movie(episodelist) (a) script and IMDB Movie(episodelist) script using proxomitron I get the error message HTTP/1.1 404 Not Found.
What seems to be the problem?
This happpens with all series when I try to run IMDB Movie(episodelist) (a) script and IMDB Movie(episodelist) script.
I can run IMDB_[EN][HTTPS]-a script, but the Imdb Movie Info-2a script gives the same error message.
All of the above scripts have the following piece of code in the ParsePage function
function ParsePage(HTML:String;URL:AnsiString):Cardinal; //BlockOpen
Begin
LogMessage('Function ParsePage BEGIN ====================== |');
LogMessage('Global Var-Mode | '+IntToStr(Mode)+' |');
Wait (pauseBeforeLoad); 
HTML:=HTMLToText(HTML);
HTML:=StringReplace(HTML,'http://imdb.com','http://www.imdb.com',True,True,False);
LogMessage('     Parsing search Movie search results');
If (0<Pos('404 Not Found',HTML)) OR (0<Pos('HTTP/1.1 404 Not Found',HTML)) Then Begin
    ShowMessage('No results.','IMDb Search Results');
    Result:=prError;
    Exit;
   LogMessage('   -------- ParsePage Error Result ( '+IntToStr(Result)+' )');
   LogMessage('Function ParsePage smSearch-prError END======================|');
   LogMessage('Function ParsePage prError END======================|');
End;
If Pos('Find - IMDb',HTML) > 0 Then Begin
.
.
.
, which is probably the cause of these problems. 
Block this part of the code for each of the above scripts. 
//If (0<Pos('404 Not Found',HTML)) OR (0<Pos('HTTP/1.1 404 Not Found',HTML)) Then Begin
//    ShowMessage('No results.','IMDb Search Results');
//    Result:=prError;
//    Exit;
//   LogMessage('   -------- ParsePage Error Result ( '+IntToStr(Result)+' )');
   //LogMessage('Function ParsePage smSearch-prError END======================|');
   //LogMessage('Function ParsePage prError END======================|');
//End;
Then do a retest for each script separately to see if the same error still occurs.