Bob's Gun Parts has parts for the .22 Erma Lugers
There's 3 different variations of the .22cal 'Luger'
There is also a 22cal version of their 380/32 Erma Luger ,,KGP-69 .22

You have to make sure which model you have as not all parts interchange.

http://www.gun-parts.com/index.html/
scroll down and click on 'Erma'
All the different models are listed in among the parts headings. He just bunches them together, but when you email specify which model you have.

I've bought parts from them to fix up one of the 380 Erma Lugers quite a while back. Never worked on one of the .22cal versions.

Numrich might well have parts also, but I' never checked then.
The 380/32 cal pistols weren't to bad.