Uploading of Avatar from front end fails

If a user attempts to upload their avatar from their profile by clicking on "Edit Avatar" and then "Upload Avatar" they briefly see a box to browse for a photo but then it's replaced with an error message of Method uploadAvatar does not exist. They can remove an Avatar with the link beneath that. However, if they go to Preference > Edit Profile they are able to upload a photo and update their avatar. Any thoughts on what is broken or missing? We can easily explain to people where they need to go to upload their avatar but it just seems odd that it's not working in just the one location. Any thoughts? Question #104332 seemed to have something similar and mentions that installing a missing mod fixed it but doesn't mention what mod and maybe it's not the same issue. Thanks!