# cs3 to cs4 migrant issue. Subclass library symbol

**URL:** https://forum.kirupa.com/t/cs3-to-cs4-migrant-issue-subclass-library-symbol/278830
**Category:** flash
**Created:** [January 6, 2009, 12:48pm UTC](https://forum.kirupa.com/t/cs3-to-cs4-migrant-issue-subclass-library-symbol/278830 "2009-01-06T12:48:45Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![philipip](https://yyz1.discourse-cdn.com/flex011/user_avatar/forum.kirupa.com/philipip/32/1231_2.png) [@philipip](https://forum.kirupa.com/u/philipip)
#### Post date: [January 6, 2009, 12:48pm UTC](https://forum.kirupa.com/t/cs3-to-cs4-migrant-issue-subclass-library-symbol/278830/1 "2009-01-06T12:48:45Z")

</div>

Hi,

I’ll get a awkward error when linking a library movieclip to a class. In flash cs3 it worked fine but in cs4 I get this error message:

5000: The class ‘Work’ must subclass ‘flash.display.MovieClip’ since it is linked to a library symbol of that type.

I have a library movieclip mapping a class called Work who subclassing Base.  
Like this;

```auto

package {
    import flash.display.MovieClip;
    import core.Base;

    public class Work extends Base {
        
        public function Work() {
            super();
        }
        
    }
}

```

```auto

package core {
    import flash.display.MovieClip;

    public class Base extends MovieClip {
        
        public function Base() {
            super();
        }
        
    }
}

```

Anyone know a sulution for this issue?