Did you compile on both computers or just laptop and copy package across to other PC?
If the latter, usually this happens as (@JacobSmall mentions) when not all of the referenced assemblies are copied across, so when dynamo loads your assembly it fails as there are dependencies missing. Also, when copying from one pc to another, windows can and will block these libraries as it assumes they are a potential threat (rightly so), best practice is to zip them up, transfer them, then on the new pc to right click on the zip and go to properties and choose unblock, extract and move to the directory of choice.
If the former, one thing to ensure is that the referenced assemblies that are not system or Dynamo and the code depends on have copy local to true in VS when building, without this you will have the same error as above as you won’t have all the required assemblies.
Also, are there any errors in the Dynamo console or pop ups when opening dynamo? And are the files in the correct package path for the version of Dynamo you are using. Sounds silly, but quite often these small mistakes are the ones that stump us the most. Ha!