When compiling any module that uses the Spider framework in 2018.3 onwards, you could see a compile error. This error is caused by the fact that as of 2018.3, the Spider framework was moved to the system modules.
To solve the problem, please remove the the complete spider framework from your user module folder. The framework is located in <PATH_TO_INSPECTOR_USER_FOLDER>/modules/acquisition2/sequence/spider (e.g. C:\Users\myusername\Inspector\modules\acquisition2\sequence\spider). Deleting the entire 'spider' folder should resolve the problem.