XP/Vista - renaming, moving & deleting files

Gudday all
I am slowly finishing off a CSV data file manipulation program.
About the last step left is rename, moving and delete files.
After all the work is done I have created 2 files that need to be both renamed and moved, a file that needs to be renamed and 3 files deleted.
The files to be moved are fortunately to stay on the same HDD but go to different folders.
(I am rapidly getting of of my depth here)
I am using rename here.

Code:

..
if ( rename("C:/ScanImages/Debug/error.dat", "C:/ScanImages/Debug/error.txt") )
      {
	perror( NULL );
	getchar();
     }
..

When I run my program I get a permission denied error. See attachment.

I am not certain what would block my permission as I thought I was in total control.

Any ideas gratefully accepted (as well as hints for moving and deleting files.)

>> I am not certain what would block my permission as I thought I was in total control.

Are you sure that the destination file doesn't already exist? If so, you'll need to delete it first.

What sebastiani said, or the file is already in use/open.

Since this is Windows, a call to GetLastError() might be more helpful in determinine the specific error that just calling perror().

Et al
I had a closer look at my code and discovered that I was trying to rename the file in question one step before it was closed.
Once I fixed the code it ran like a charm.
Thank you for your help.