If you have no missing references, then I am a bit confused about how this works. So I am going to ask a question that might sound strange, You say that this works on Ac2016 but does not work on Ac2007, BUT you mention something about the server being on 2007.
Remembering that references are actually a REGISTRY function and that it is possible for the same app to have errors on one machine but not another one, verify for me that:
When you say "running on an Ac2007" you mean that the front end of the app is running on a machine with Office 2007 installed.
When you say "running on an Ac2016" you mean that the front end of the app is running on a machine with Office 2016 installed.
When you say something about running on a 2007 server, you mean that the front end of the app is running on a machine set up as a server and that it is running with Office 2007 installed.
And verify that at NO time are you running with an Access 2007 installed separately on a machine with Office 2016 installed. Because it is possible to have Office Home, which DOES NOT INCLUDE a version of Access, which in turn means you have to manually install Access separately.
I'm trying to eliminate mixed-environment cases because they have been known to be troublesome. So if this sounds a little pedantic, it is only to be sure of the environment before we go completely crazy here.
I also would like to suggest that you look at Gasman's suggestion of DECOMPILE, which is a command-line function. If you decompile the app, then go in manually and use the toolbar's Debug >> Compile option, that forces ALL CODE to be recompiled. At that point, if you have corruption or a missing reference that isn't so obviously missing, it will show up. If so, it will point to an immediate solution.
Here is a link on the topic:
https://www.fmsinc.com/MicrosoftAccess/Performance/Decompile.asp
FMS is a good source for some documentation when you do a web search for a topic and their name comes up in response. So don't be too afraid of them. At worst, they'll have a little bit of self-advertising.