Hello,
every single instance of ALM uses their own version of the QC explorer, other versions create conflicts and the best is to suit the recommendations from the following page:
https://hpln.hp.com/page/hp-alm-explorer-add
Ariel Blanco
HP QC/ALM support team
(If this post or any other post helps to resolve your issue or query, please mark the thread as solved)
(Posts and opinions made here are my own and do not reflect the opinions of my employer HP in any way)