Problem MaskedTextField

Flow
1

I´m using vaadin with version 6.7.6 e gwt with version 2.4.0. Every time that i add the component MaskedTextField inside a window, the debug acused this error:

avaScriptException: (TypeError): b is undefined stack: Otb([object Object]
,(void 0))@http://localhost:8080/VAADIN/widgetsets/br.com.allbrax.nubeoperatios.CustomWidgetset/03B17E01C791239D3753CD48F3B25C3F.cache.html:3590 Ttb([object Array]
,[object Object]
)@http://localhost:8080/Nube-Operatios-Regente-web-6.0-SNAPSHOT/VAADIN/widgetsets/br.com.allbrax.nubeoperatios.CustomWidgetset/03B17E01C791239D3753CD48F3B25C3F.cache.html:3700 bsb([object Array]
,[object Object]
)@http://localhost:8080/Nube-Operatios-Regente-web-6.0-SNAPSHOT/VAADIN/widgetsets/br.com.allbrax.nubeoperatios.CustomWidgetset/03B17E01C791239D3753CD48F3B25C3F.cache.html:3700 bsb([object Array]
,[object Object]
)@http://localhost:8080/Nube-Operatios-Regente-web-6.0-SNAPSHOT/VAADIN/widgetsets/br.com.allbrax.nubeoperatios.CustomWidgetset/03B17E01C791239D3753CD48F3B25C3F.cache.html:3700 zyb([object Array]
,[object Object]
)@http://localhost:8080/Nube-Operatios-Regente-web-6.0-SNAPSHOT/VAADIN/widgetsets/br.com.allbrax.nubeoperatios.CustomWidgetset/03B17E01C791239D3753CD48F3B25C3F.cache.html:3703 Mkb([object Object]
,[object Array]
,[object Object]
)@http://localhost:8080/Nube-Operatios-Regente-web-6.0-SNAPSHOT/VAADIN/widgetsets/br.com.allbrax.nubeoperatios.CustomWidgetset/03B17E01C791239D3753CD48F3B25C3F.cache.html:3630 wkb([object Array]
,[object Object]
)

I try to update to vaadin version 6.7.8 but the error continue. Anyone can help me?

Thanks for attention