I'm afraid I don't understand your workflow... How do you get your PrPro multicam sequence into AE ?.. How do you get AE comp into PrPro ?..
Normally you can start building your dynamic links either from PrPro or from AE.
If you start from PrPro
1. Select a clip or a group of clips in the timeline you want to replace with AE composition
2. Right-click and choose 'Replace With After Effects Composition'
3. Do your magic within AE
4. When you finish, just switch back to PrPro - all changes you've done should be automatically shown in the timeline (not to forget to render preview with 'Render Entire Work Area' command)
If you start from AE
1. Create your composition within AE
2. Switch to PrPro, choose 'File -> Adobe Dynamic Link -> Import After Effects Composition...'
3. Treat your dynamically linked AE comp as an ordinary asset
If nothing else helps, try to
1. Deactivate and then reactivate your applications
2. Clean up Media Cash Database...
Actually, I get the error about Dynamic Link when I try "Replace With After Effects Composition". I'm starting from PP and nothing updates, even after rendering the work area.
Not sure I follow you... You get the error message when you try to replace dynamically linked comp with a new one?.. Or you get that message right after your first attempt to replace multicam sequence with AE comp?..
Anyway, you have two choices:
1. If you lack of time, try do deactivate and then reactivate your applications. If it doesn't help, render lossless intermediate out of AE and use it instead of dynamically linked comp so as to finish your PrPro project.
2. If you have enough time to experiment, and deactivating and reactivating doesn't help, move further with cleaning up your Media Cash Database...