Have you looked at the characteristics of the window in the object map? Chances are that every time the window is generated, there is some unique set of numbers/characters at the end of the window name that changes. You will have to replace that unique string with wildcards.
I came across similar kind of problem and this was what i did ,if u have any further clarification please let me know.
This may be some thing to with the object recognition technique you are using, it may be one of the few
1. The title/parent title of the window may be having a variable thing like current date, current time,version number etc.,
Next time you come across this problem just do the following
1. Store the changed object into object repository with a temp name "Temp_OBJ"
2. Now Select this Temp_OBJ and already learnt object in the repository and Select Options-->Compare
3. This funtion will tell u the difference between the object and based on that u can modify the object recognition techniques
You can modify the parent title/title to have some wild card characters etc.,
This is almost certainly caused by a unique set of characters at the beginning or end of the window name. As Darrel says, you will need to replace these with wildcards in the Object Map.
CRK's suggstion is a good way of identifying these.
I would warn against adopting isumi's suggestion because this is likely to cause you a great many problems, especially if you have error message windows in your system. It will attach to the message window and then attempt to action the next command, which of course it won't be able to do and therefore you will again ahve a Runtime Error. The only way to avoid this would be to have some (probably) quite complex error handling routine.
My solution would be to go with Darrels/CRK's suggestion and put whatever error handling is required in each script.