I'm stuck in a loop.

I'm hosted at wp engine, just installed the mpmudev plugin, and i when i try to install another plugin , by example antisplo, i click in the wp admin on "download plugin", then get to the antisplog page on wpmudev.org, then click on install, then pipup to select wich site, i choose the only one i have, then it come back to my wp admin without installing it, as if i 'm stuck in a loop.