Problems adding files to the archive

Hello,

We are getting errors when we are trying to add files to archive

ERROR: Can not add the file '<filename>' to ''!Access to the path '<Target_name>.appl.zip.571.tmp' is denied.

Some times it is working properly but sometimes getting this error.

We are using this method to add files to the archive

public void Add(string fileName, CompressionMethod compressionMethod)
        {
            if ( fileName == null ) {
                throw new ArgumentNullException("fileName");
            }

            if ( !ZipEntry.IsCompressionMethodSupported(compressionMethod) ) {
                throw new ArgumentOutOfRangeException("compressionMethod");
            }

            CheckUpdating();
            contentsEdited_ = true;

            ZipEntry entry = EntryFactory.MakeFileEntry(fileName);
            entry.CompressionMethod = compressionMethod;
            AddUpdate(new ZipUpdate(fileName, entry));
        }

Thanks in advance......