NetJoinDomain

I am trying to connect to a domain using the NetJoinDomain API. I can successfull use it to change the workgroup. But when trying to change the domain I get one of two errors, using the same input. I either get "No such domain" or "No mapping for the Unicode character exists in the target multi-byte code page." This is using the same exact inputs, I have hard coded the inputs in for debuging purposes.

What am I doing wrong?

Also for some reason I have to convert the strings into char arrays and insert a null value between each character. Anybody know why?

VB Code:

Private Declare Function NetJoinDomain _
    Lib "NETAPI32.dll" (ByVal lpServer As String, _
    ByVal lpDomain As String, ByVal lpAccountOU As String, _
    ByVal lpAccount As String, ByVal lpPassword As String, _
    ByVal fJoinOptions As Int32) As Int32
 
 
Public Sub ChangeDomain()
        Dim d() As Char
        Dim u() As Char
        Dim p() As Char
 
        ' I replaced what the actual values are, since they were my username and password to the company domain
        'InsertNulls is a function that I created to convert the strings to char arrays and insert null chars between each value
        d = insertNulls("myDomain")
        u = insertNulls("myUserName")
        p = insertNulls("MyPassword")
 
 
        err = NetJoinDomain("", d, "", u, p, JoinOptions.NETSETUP_DOMAIN_JOIN_IF_JOINED Or JoinOptions.NETSETUP_JOIN_DOMAIN)
End Sub