input past end of file

I am receiving this error.
Category = Microsoft VBScript runtime
Number = 0x800A003E
Description = Input past end of file

Here is the code

<%
Dim fsoObject                   'File System Object
Dim tsObject                    'Text Stream Object
Dim filObject                     'File Object
Dim lngVisitorNumber          'Holds the visitor number
Dim intWriteDigitLoopCount 'Loop counter to display the graphical hit count
Set fsoObject = Server.CreateObject("Scripting.FileSystemObject")
Set filObject = fsoObject.GetFile(Server.MapPath("/hits.txt"))
Set tsObject = filObject.OpenAsTextStream
lngVisitorNumber = CLng(tsObject.ReadAll)
lngVisitorNumber = lngVisitorNumber + 1
Set tsObject = fsoObject.CreateTextFile(Server.MapPath("/hits.txt"))
tsObject.Write CStr(lngVisitorNumber)
Set fsoObject = Nothing
Set tsObject = Nothing
Set filObject = Nothing
%>


Here is the line with the error
lngVisitorNumber = CLng(tsObject.ReadAll)

There hasn't been any error on this in over 200,000 hits. What could be the problem?

Thanks for the reply!No, I haven't checked my webhost yet. It's odd though. There has been no error then there was an error on 3 clicks in a row then there was no errors again. All this without any changes. Next thing I will check is my webhost status.