Common errors/resulting messages in common lisp (gcl specifically):

1. You put the #! line in a file then try to load it, i.e. (load "filename.cl")
   Error message: "BROKEN AT LOAD"

2. You're missing a ) somewhere
   Error message: "END-OF-FILE :STREAM <path-to-your-lisp-file>"

3. You're missing a "
   No error message, it just hangs waiting to find another "

4. You forget the ' in front of a data list
   or you put ( ) around  a data value, e.g. (3)
   Error message: TYPE-ERROR :DATUM the front element of the list :EXPECTED-TYPE FUNCTION

5. You pass an incorrect data type to an operator or function
   Error message: TYPE-ERROR :DATUM the value you passed :EXPECTED-TYPE the kind of data it expected

6. You use an undeclared variable (or undeclared in the current scope)
   Error message: UNBOUND-VARIABLE :NAME your variable name

7. You use an undeclared function (or undeclared in the current scope)
   Error message: UNBOUND-FUNCTION :NAME your function name
              or: UNDEFINED-FUNCTION :NAME your function name

8. You call a function with the incorrect number of arguments
   Error message: PROGRAM ERROR function name REQUIRES more/less THAN n ARGUMENTS
      where n is the number of arguments you actually passed

9. You have infinite recursion
   Error message: Frame Stack overflow