stack trace of the exception is:
message: at UiPath.PDF.PdfReader…ctor(String filePath, String password) at UiPath.PDF.Activities.PDF.GetPDFPageCount.Execute(CodeActivityContext context) at System.Activities.CodeActivity.InternalExecute(ActivityInstance instance, ActivityExecutor executor, BookmarkManager bookmarkManager) at System.Activities.ActivityInstance.Execute(ActivityExecutor executor, BookmarkManager bookmarkManager) at System.Activities.Runtime.ActivityExecutor.ExecuteActivityWorkItem.ExecuteBody(ActivityExecutor executor, BookmarkManager bookmarkManager, Location resultLocation)
Are the Studio versions identical? (local vs. prod)
If not, make sure your assembly files match. The error is pointing out that your dependencies are not exactly in the right state. You should check your activity package integrity.
I have fixed this issue by overwriting the .nuget\packages folder (you can find it in C:\Users\yourUser.nuget\packages) from local to prod environment. This folder stores your .dll assembly files that are used by the activity packages.