CryptAcquireContext "The Keyset is not defined" Error - vb.net

Question

CryptAcquireContext function returns FALSE with The Keyset is not defined error message. Here is my code.
<DllImport("advapi32.dll", CharSet:=CharSet.Auto, SetLastError:=True)>
Public Shared Function CryptAcquireContext(ByRef hProv As IntPtr, ByVal pszContainer As String, ByVal pszProvider As String, ByVal dwProvType As Int32, ByVal dwFlags As UInt32) As Boolean
End Function
<DllImport("advapi32.dll", SetLastError:=True)>
Public Shared Function CryptCreateHash(ByVal hProv As IntPtr, ByVal Algid As Int32, ByVal hKey As IntPtr, ByVal dwFlags As Int32, ByRef phHash As IntPtr) As Boolean
End Function
<DllImport("advapi32.dll", SetLastError:=True)>
Public Shared Function CryptHashData(ByVal hHash As IntPtr, ByVal pbData() As Byte, ByVal dwDataLen As Int32, ByVal dwFlags As Int32) As Boolean
End Function
Public Const PROV_RSA_FULL As Int32 = 1
Private Const CRYPT_VERIFYCONTEXT As UInt32 = &HF0000000UI
Private Function GetHash(ByVal text As String) As Boolean
Dim bResult As Boolean = False
Dim hProv As IntPtr
Dim hHash As IntPtr
If CryptAcquireContext(hProv, vbNull, vbNull, PROV_RSA_FULL, CRYPT_VERIFYCONTEXT) Then
If CryptCreateHash(hProv, CALG_SHA1, 0, 0, hHash) Then
If CryptHashData(hHash, Encoding.ASCII.GetBytes(text), text.Length, 0) Then
Dim bHash(20) As Byte
Dim dwHashLen As Int32 = Marshal.SizeOf(bHash)
bResult = CryptGetHashParam(hHash, HP_HASHVAL, bHash, dwHashLen, 0)
If bResult = True Then
//Rest of string operations
End If
End If
End If
End If
Dim errorMessage As String = New Win32Exception(Marshal.GetLastWin32Error()).Message
MsgBox(errorMessage)
Return bResult
End Function
Do you have any idea about what i'm doing wrong?
Thanks