Have you marked the files as releases? I think you may need to do that. I'm not familiar with the internals of curseforge unfortunately, you could try asking on the bukkit forum (a lot of users there are familiar with curseforge) or you could create a support ticket at support.curse.com and the dev team will get back to you asap. Sorry I couldn't be more help!
After I put my world on CurseForge, and put the download, I came back and put the widget on my map (world) page, and it says that there are no files available for download. So I went onto Curse and looked at the world, there was no download button.
Ok, thanks!
Thanks!