Currently it's easy for hackers to exploit the code of winks to display any flash movies on a users computer for any amount of time.Source: Neowin => check out the comments over at NeoWin to find a workaround if you're having problems signing in with MSN7.
MSN took the decision following the public announcements of the exploits. We're unsure whether 'winks' are going to be axed from MSN Messenger 7 or whether MSN are merely revamping them to be included in later betas.
In other news, The Messenger team will be implementing a CVR update that will force all existing MSN Messenger V7.0 users to downgrade to V6.2. This CVR is scheduled to start on 6 Oct 2004. Anyone running MSN Messenger V7.0 build 0205 will need to downgrade. If you do not downgrade, you will be unable to sign into the Messenger service. We're unsure whether this will effect other builds.
Microsoft to force MSN Messenger 7 users to downgrade to MSN 6

Neowin reports that Microsoft have not only delayed the official beta of MSN 7 but they are also planning to remove certain features from the beta. According to sources close to MSN, MSN Messenger 7 beta will ship without "winks" and deluxe display pictures.