The solution I have found is that I stopped downloading
enwiki-latest-pagelinks.sql.gz on my laptop (wifi) using free download
manager.
I started the download of categorylinks file on my pc (without any download
accelerator).
Finally I restarted the 1st download.
The two downloads are now happenning simultaniously.
Thank you very much indeed for your responses.
Truly yours
Khalida Ben Sidi Ahmed