link error on QMetaObject

Dear all,

I am compiling my program using QT 4.4.0. I have a form .ui generating the cpp and moc file.
this component is inside a dll library.

when i use this component in the main program, I have link error as follow

LNK2019: unresolved external symbol "public: static struct
QMetaObject const LoginBox::staticMetaObject"
(?staticMetaObject@LoginBox@@2UQMetaObject@@B) referenced in function
"public: static class QString __cdecl LoginBox::tr(char const *,char
const *)" (?tr@LoginBox@@SA?AVQString@@PBD0@Z)

LoginBox is the class name of my form .ui

I checked the loginbox.cpp which is generated by uic3 containing the Q_OBJECT macro
and I have the moc_loginbox.obj created

I dunno what I have done wrong, please help me

thanks alot