Which plug-in, in particular, are you asking about?
NewBlueFX, for instance, has several. I also think that NeatVideo will work in PrE 11.
It will depend on the exact plug-in, and the developer's Web sites should list all host applications.
Did you contact the source of these plug-ins to find out if they have compatibility beyond Premiere Pro CS5?
No I havent, probably why it is not working.
Have contacted NewBlueFX to see what they have that is compatible with PrE 11.
Any other suggestions for effects plug-ins?
A just in case note...
Many of the Premiere Elements effects are from NewBlue so make sure that you are not considering a bundle of effects in which over half are already included with the program.
The following is a 2011 Adobe Forum thread on your topic that you may want to check out...
As ATR points out, contacting the publisher of that set of plug-ins, to determine if they can be hosted by PrE, will get you the answer.
Some plug-ins can be hosted by many different programs, but a lot, can only be hosted by certain programs. For instance, though PrPro can host some After Effects plug-ins, many are After Effects ONLY.
While PrE and PrPro have some similarities, they are different programs. For instance a lot of BlackMagic Effects will work in PrPro, but not in PrE.
On my PC plug-ins are stored in C:\Program Files\Adobe\Adobe Premiere Elements 11\Plug-ins\Common.
Try adding your plug-in there and see if it works.
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