When I'm browsing an issue using it's direct URL (https://jira.lyit.ie/browse/JLOG-17) I can paste screenshots using the attach screenshot feature. When I select the same issue on the agile board and select the attach screenshot feature it opens a new tab to this URL:

https://jira.lyit.ie/secure/ShowAttachScreenshotFormAction!default.jspa?id=12002&returnUrl=%2Fsecure%2FRapidBoard.jspa%3FrapidView%3D10009%26view%3Ddetail%26selectedIssue%3DJLOG-17%26quickFilter%3D10023

And on this page I can't paste any screenshots...