Unusual Errors at application compilation

Unusual Errors at application compilation

I have following class described below. in Library 'Paket'
class NotificationType : public Enumeration
{
protected:
NotificationType(QString name): Enumeration(name){}
public:
static const NotificationType ERROR;
static const NotificationType WARNING;
static const NotificationType NORMAL;
static const NotificationType ACKNOWLEDGE;
static const NotificationType NONE;
static NotificationType fromString(QString name);
};
when i compile this library i got no errors.
in my application i use this class. when i compile my application i got
following errors ( indicating to this class in 'Packet' Library not in my
application.)
C2059: syntax error : 'constant'
C2238: unexpected token(s) preceding ';'
class NotificationType : public Enumeration { protected:
NotificationType(QString name): Enumeration(name){} public: static const
NotificationType ERROR; <-- Error Occurs Here static const
NotificationType WARNING; static const NotificationType NORMAL; static
const NotificationType ACKNOWLEDGE; static const NotificationType NONE;
static NotificationType fromString(QString name); };
can any one explain this ?