My remote team can't open my After Effects files. Error: Source file has a bad header

I work remotely using After Effects and DropBox. We are very careful to make sure everything is saved on DropBox, all links, assets, and project files, and that the DropBox files are synced locally to the team member's computer.

However, whenever I build an after effects project file and my partner opens it on her computer, she's faced with a barrage of errors for every link, saying that the source file has a bad header and other error messages. For example, I created a new project file with a bunch of JPGs linked to the project. When she opened the project file, she got the message "The Source file has a bad header" and that AE can't read the 'GPEJ' file. For some reason it's reading the JPEG file backwards? Once she clicks through all the error messages, she still can't relink the files manually. Only when she goes to the asset folder, opens each file, does her computer let them be linked.

Does anyone have any solutions to this?? It's been a big problem in our workflow and any advice or other systems reccomendations would be super helpful.