change the password minimum length requirement in web.config:
add name="AspNetSqlMembershipProvider" type="System.Web.Security.SqlMembershipProvider" connectionStringName="SiteSqlServer" enablePasswordRetrieval="true" enablePasswordReset="true" requiresQuestionAndAnswer="false" minRequiredPasswordLength="7" minRequiredNonalphanumericCharacters="0" requiresUniqueEmail="false" passwordformat="Encrypted" applicationName="DotNetNuke" description="Stores and retrieves membership data from the local Microsoft SQL Server database"
by default it is set to 7
as for the other error message, this could be due to some fields being populated in AD that get copied over, while others are missing in AD. I have an error similar to this when users don't have the region information filled in on the AD account.