Condition of type: SIMPLE-ERROR

The packages

  ((UIOP/OS . #<UIOP/OS package>) (UIOP/PATHNAME . #<UIOP/PATHNAME package>))

were referenced in compiled file

  NIL

but have not been created

Available restarts:

1. (IGNORE) Ignore the error, and try the operation again

Top level in: #<process TOP-LEVEL>.

Tried ECL 16.1.4 on Ubuntu and ECL 16.0.0 on OSX.

What is the reason of this error, and how to fix it?