msSaveImage(): Unable to access file error

[Manjiri Andhare]

I'm trying to run Itasc workshop demo, on Windows 2000 with IIS.
I'm getting this error message:
msSaveImage(): Unable to access file.
(C:\Inetpub\wwwroot\MapServer\Docs\tmp\ITASCA10970029431608.png)
My wokshop demo files are in C:\Inetpub\wwwroot\MapServer\
And my mapserver program i.e. mapserv.exe is in :
C:\Inetpub\wwwroot\MapSErver\cgi-bin\mapserv.exe
I have created folder Docs\tmp under C:\Inetpub\wwwroot\MapServer, and i
have given read/write rights to Doc\tmp folder.
As per my knowledge, I'm using c:\Inetpub\wwwroot\MapServer\Docs\tmp\ to
store the files created by mapserver i.e. for "map_web_imagepath" in
index.html.
But when i run the application, I'm getting the error that "Unable to
access file.
Do i need to specify anything else?