Problem with preferences after dwploy zimlet

[mila_07]

Hello and sorry for my english.

I develop a simple zimlet that recover some data after a call to another server.
It works, It works in ZD and ZCS both.

But I have a problem: after deploy this zimlet, when I click in Preferences Tab this crash.

There is this javascript error:

next.getHtmlElement is not a function
if (next) Dwt.delClass(next.getHtmlElement(), DwtToolBar._NEXT_PREV_RE, DwtToolBar.SELECTED_NEXT);

This is 378th row of DwtToolBar.js.
If I undeploy my zimlet Preferences Tab don't crash.

Someone can help me?

Thak you