The table column you used to store the file name is stored as the string <base_dir>/<reference_to_external_file>, where <base_dir> is the base directory where the blobfile is located, and <reference_to_external_file> is the exact string found in the contents column in the XML file.
The base directory can be set initially using the -f option of the UltraLite Java edition database load utility. Relative
filenames are resolved with the blob_file_base_dir option value. If the file name does not begin with the prefix file://, UltraLite then prepends the file name with the option value before attempting to open it.