"about:config" without the quotes

hit enter click on "I understand and wish to continue" if prompted
now look for

"browser.cache.check_doc_frequency" double click and change its value to 1 click ok

now look for
"browser.cache.disk.capacity" double click and change its value to 0 click ok

close the firefox browser(or any mozilla based browser) and open it then try the mp3 player logout and back in
i have tried this numerous times and it always works