Hi, I am experiencing the same issue, I can only add that I upgraded my 9.0.1 windows server from FP4 to FP5 and the problem persists.

Thanks

Roberto

Hello, 

On 3/9/16 I reported this issue to Bugzilla (#1255139) as well, and I have an SPR and  APAR with IBM on it:  SPR#JALAA7VSRE) and (APAR LO88282 .  This also occurs in iNotes/Domino 9.0.1 FP5 and is completely attributable to the combination of Domino/iNotes with Firefox 45.0.   Other browsers seem to work fine.  You can downgrade your FF to 44.0. x per https://support.mozilla.org/en-US/kb/install-older-version-of-firefox?redirectlocale=en-US&redirectslug=Installing+a+previous+version+of+Firefox

After downgrading, be sure to uncheck the automatic update option.

(please delete me)

Mozilla is already aware of the Probelm as you can see here:

https://www.fxsitecompat.com/en-CA/docs/2015/jar-protocol-support-has-been-disabled-by-default/

It results from the new default setting for "network.jar.block-remote-files" in about:config, whitch is set to true since FF45.
FF45.0.1 will get it disabled again.

Ups, have to check this forum more often. Thanks for your answers, the reason is clear now. In the link Michael Polanz provided, Mozilla states that "No other browsers support this Java archive protocol so far.". So, why is iNotes for Firefox using this, is another question I am doing my self now. Anyway, we have a solution, sadly it involves setting a config manually in Firefox. (I use beta builds).