C#

using (DirectoryEntry de = new DirectoryEntry())
{            
de.Path = "LDAP://celticrain/OU=Wrox Press, DC=eichkogelstrasse, DC=local";
DirectoryEntries users = de.Children;

DirectoryEntry user = users.Add("CN=John Doe", "user");
user.Properties["company"].Add("Some Company");
user.Properties["department"].Add("Sales");
user.Properties["employeeID"].Add("4711");
user.Properties["samAccountName"].Add("JDoe");
user.Properties["userPrincipalName"].Add("JDoe@eichkogelstrasse.local");
user.Properties["sn"].Add("Doe");
user.Properties["givenName"].Add("John");
user.Properties["userPassword"].Add("someSecret");
user.CommitChanges();
}

using (DirectoryEntry de = new DirectoryEntry())
{
de.Path = "LDAP://celticrain/CN=John Doe, CN=Users, DC=eichkogelstrasse, DC=local";
de.Invoke("SetPassword", "anotherSecret");
de.CommitChanges();
ActiveDs.IADsUser user = (ActiveDs.IADsUser)de.NativeObject;
user.SetPassword("someSecret");
user.AccountDisabled = false;
de.CommitChanges();
}

• Make sure you're not using Unicode methods without the Unicode layer for Win9x
  
• Make sure you're not using methods that only work on Windows NT (such as the Network Management API or the GINA methods)
  
• If you do use Unicode, make sure you make two builds: 1 for ANSI and 1 for Unicode. Make sure you install the appropriate build on the appropriate platform.