How to intercept error message "IF Codeunt.run"

What about technical upgrade to NAV 5.0? Than you can use the new function as Mattrax wrote...

nope, that is not possible for now. But I thought of a soulution like this. First rewrite all errors like this, insted of using

ERROR(Text013)

, I would write

ErrString := Text013;
ERROR(ErrString);

. Then write a function in CU to retrieve ErrString. And if the CU fails to run, I would call my new function. But that doesn't seem the best way

You cannot use it in this way directly - when you run the codeunit through CODEUNIT.RUN, you cannot call some specific function of the same instance of the codeunit. You will need to use Singleinstance CU. Do not forget that many things could happen in nested objects, through TESTFIELDS etc...

well this is not true, you can do it without any single instance cu. All you need is to declare the CU you are running and make sure the variables are global in that CU. But still this is not the method I want to use.

OBJECT Codeunit 50001 Test Post
{
  OBJECT-PROPERTIES
  {
    Date=24.02.10;
    Time=11:12:07;
    Modified=Yes;
    Version List=;
  }
  PROPERTIES
  {
    OnRun=BEGIN
            ErrStr := Text001;
            ERROR(ErrStr);
          END;

  }
  CODE
  {
    VAR
      Text001@1000000000 : TextConst 'ENU=This is the error message!';
      ErrStr@1000000001 : Text[100];
    ;

    PROCEDURE GetErrStr@1000000001() : Text[100];
    BEGIN
      EXIT(ErrStr);
    END;

    BEGIN
    END.
  }
}

OBJECT Codeunit 50002 Test Msg. Interception
{
  OBJECT-PROPERTIES
  {
    Date=24.02.10;
    Time=11:15:04;
    Modified=Yes;
    Version List=;
  }
  PROPERTIES
  {
    OnRun=BEGIN
            IF NOT TestPostCU.RUN THEN BEGIN
              ErrStr := TestPostCU.GetErrStr;
              MESSAGE(ErrStr);
            END;
          END;

  }
  CODE
  {
    VAR
      TestPostCU@1000000000 : Codeunit 50001;
      ErrStr@1000000001 : Text[100];

    BEGIN
    END.
  }
}