Response.Redirect Issue

[liunx]

Can someone tell me why this form:

<form name="member_login" method="post" action="default.asp">
<div style="font-size:8pt;font-weight:bold;
text-align:center;border:1px inset #99CCFF;color:#003399;background-color:#00ff99">
<img src=http://www.htmlforums.com/archive/index.php/"/graphics/login.gif" alt="Member Login" WIDTH="100" HEIGHT="15 /">
</div>
<div style="margin-top:5px;font-size:8pt">
User ID:
<div>
<input type="text" name="user_name" id="user_name" style="font-size:8pt" size="12" maxlength="12" />
</div>
</div>
<div style="margin-top:10px;font-size:8pt">
PIN:
<div>
<input type="password" name="pin" id="pin" style="font-size:8pt" size="12" maxlength="12" />
</div>
</div>
<div style="text-align:center;margin:10px;font-size:8pt">
<input type="hidden" name="submit_this" id="submit_this" value="submit_this" />
<input type="submit" name="submit_login" id="submit_login" value="Login" style="font-size:8pt" />
<br />
<a href=http://www.htmlforums.com/archive/index.php/"javascriptop('misc/get_login.asp',400,400)" style="font-size:8pt">Forgot Login?</a>
</div>
</form>


would submit correctly on my machine (within my domain), but not from outside the domain? Here is the asp:


ElseIf Request.Form.Item("submit_this") = "submit_this" Then
Set rs = Server.CreateObject("ADODB.Recordset")
sql = "SELECT UsersID, PIN, FirstName, LastName, Role FROM Users WHERE UserID = '" & Request.Form.Item("user_name")
sql = sql & "' AND PIN = " & Request.Form.Item("pin") & " AND Active = 'y'"
rs.Open sql, conn, 1, 2
If rs.RecordCount > 0 Then
Session("my_id")= rs(0).Value
Session("user")= rs(2).Value & " " & rs(3).Value
Session("role") = rs(4).Value
Response.Redirect "how_to/how_to.asp"
Else
sErrMsg = "I am sorry. Your information was not recognized."
End If
rs.Close
Set rs=Nothing


Thanks~