master page virtual path ......directive error

[YY]

Every time I add the directive <%@ MasterType
VirtualPath="~/SttAllocation.Master" %>


Server Error in '/' Application.

Compilation Error
Description: An error occurred during the compilation of a resource required
to service this request. Please review the following specific error details
and modify your source code appropriately.

Compiler Error Message: CS0030: Cannot convert type
'SttAllocation.SttMaster' to 'ASP.sttmaster_master'

Source Error:

Line 148: public new ASP.Sttmaster_master Master {
Line 149: get {
Line 150: return ((ASP.sttmaster_master)(base.Master));
Line 151: }
Line 152: }


Source File: c:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET
Files\root\d357ec28\684c5874\App_Web_availablecrn.aspx.d4d077b3.vixdnvqk