If the connection is slow, try GNU wget. (manual).
It can be obtained from the web, if not available.

A file selection can be made by filling in the wildcard after the -A option.
To get all fitsfiles of EK050F copy next line to your commandwindow:

wget --http-user username --http-passwd password -t45 -l1 -r -nd archive.jive.nl/exp/EK050F_220506/fits -A "ek050f*"
Replace username and password with actual values before executing the command.
The checksum file can be used to verify the checksum of all datafiles using:
md5sum -c ek050f.checksum (on unix systems).