[plt-scheme] Access denied while versioning

While versioning mzscheme (360 distribution WinXP) with 

C:\mz-360>mzscheme -mvqL winvers.ss setup


I get 

C:\mz-360>open-input-output-file: cannot open output file:
"C:\mz-360\iconv.dll"
 (The process cannot access the file because it is being used by another
process.; errno=32)


Can you help, please?

Antonio