I was recently asked to install Oracle 8.1.7 on a Linux machine (RH 9 if you feel it's important). After the installation I imported a full database dump that I earlier exported from another system (8.1.6 on Solaris). Everything seems to be fine except that I'm getting a strange error:

When attempting to execute a procedure that takes a BOOLEAN value as one of its parameters I see this error:
call some_procedure(1,2,true)
ERROR at line 1:
ORA-06576: not a valid function or procedure name
I understand that the definition of the boolean literal TRUE is somehow missing or invalid. Is there a way to correct this (short of reinstalling the whole thing from scratch hoping the problem will go away)?