Error message when importing mesh

I have looked all over for some help on this and haven't been able to find anything! I've got a pretty decent amount of experience with mesh editing and using blender.... I am trying to edit the mesh of a carriage so that the door is open. I've done this on other projects and it worked just fine, but every time i try to import the new mesh into sims 4 studio, i get this error message. The thing is, i even tried to export the exact, unedited mesh from sims 4 studio and then directly back into it without doing anything and i get the same error message... so I am thinking it was possibly created with some other program? I don't know, I'm clueless on how to proceed. Would be happy to upload the package and blender files for someone to help. You can tell by looking at the mesh in edit mode in blender that it is made very, very differently than most blender meshes are made. Here is the error message I received from importing both the unedited and edited versions of the same mesh into Sims 4 Studio:

The Sims 4 Studio - Version 3.1.4.5
System.AggregateException: One or more errors occurred. ---> System.IO.FileNotFoundException: Could not find file 'C:\ProgramData\S4Studio\Scripts\0aaea315-32b8-44e3-9f8b-f70e18e1430b\s4s.out.mlod'.
at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)
at System.IO.FileStream.Init(String path, FileMode mode, FileAccess access, Int32 rights, Boolean useRights, FileShare share, Int32 bufferSize, FileOptions options, SECURITY_ATTRIBUTES secAttrs, String msgPath, Boolean bFromProxy, Boolean useLongPath, Boolean checkHost)
at System.IO.FileStream..ctor(String path, FileMode mode, FileAccess access, FileShare share)
at S4Studio.ViewModels.ObjectLodItem.ImportMesh(BlenderUtilities blender_util, String blender_path)
at S4Studio.ViewModels.ObjectLodItem.<>c__DisplayClass49_0.<ImportMesh>b__0()
at System.Threading.Tasks.Task.InnerInvoke()
at System.Threading.Tasks.Task.Execute()
--- End of inner exception stack trace ---
---> (Inner Exception #0) System.IO.FileNotFoundException: Could not find file 'C:\ProgramData\S4Studio\Scripts\0aaea315-32b8-44e3-9f8b-f70e18e1430b\s4s.out.mlod'.
File name: 'C:\ProgramData\S4Studio\Scripts\0aaea315-32b8-44e3-9f8b-f70e18e1430b\s4s.out.mlod'
at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)
at System.IO.FileStream.Init(String path, FileMode mode, FileAccess access, Int32 rights, Boolean useRights, FileShare share, Int32 bufferSize, FileOptions options, SECURITY_ATTRIBUTES secAttrs, String msgPath, Boolean bFromProxy, Boolean useLongPath, Boolean checkHost)
at System.IO.FileStream..ctor(String path, FileMode mode, FileAccess access, FileShare share)
at S4Studio.ViewModels.ObjectLodItem.ImportMesh(BlenderUtilities blender_util, String blender_path)
at S4Studio.ViewModels.ObjectLodItem.<>c__DisplayClass49_0.<ImportMesh>b__0()
at System.Threading.Tasks.Task.InnerInvoke()
at System.Threading.Tasks.Task.Execute()<---