Converting byte(n) to String to do Replace(xxx)

"My friend" is having problems doing replacement in an byte array.

"He" has a funktion(Inet-MS internet Transfer control 6.0) that returns a byte array, this array consists of text.
In order to make this replacement he tries to use the Replace() funktion, but in order to do this he first has to convert this byte array into a string.

This function is used:
--------------------------------
Function MyByteToCstr(ByteArr() As Byte) As String

Dim RetVal As String
Dim i As Integer


RetVal = ""

For i = 0 To UBound(ByteArr()) - 1
    RetVal = RetVal & Chr(CInt(ByteArr(i)))
Next i

MyByteToCstr = RetVal
End Function
-----------------------------------------

This function will give an errormessage "OVERFLOW (-6)"...
This overflow error is thrown when the byte array is to large(we used 67 000 byte). 1500 byte works fine.

How could "he" convert this byte-array, does anyone have another idea how "he" could make a replace in a byte-array?

Any ideas would make me, I mean "he" happy ;)