Class MY_lang not found in application/third_party/datamapper/system/Lang.php(34)

[eluser]chantheoun[/eluser]
HI all,
Now I meet a problem with
"Class MY_lang not found in application/third_party/datamapper/system/Lang.php(34)"

when I uploaded a new the project to server it showed the above error. I have database and already uploaded the whole project to server. In my localhost the project work fine but when I finished and uploaded, it has error like this.

If all of you have solution, please kindly share.

Regards,

Chantheoun