lex query: "Too many right contexts"

[Bill Silvert]

Whenever I use a right context in a long lex program I get the message:
	(Error) Too man right contexts
And if I eliminate enought statements which do NOT have right contexts
it works.  Specifically, I am working on a cross-reference program for f77,
which has lines like:
	WRITE	;
to ignore reserved words, and I would like to recognize assignement statements
with lines such as:
	[A-Z][A-Z0-9]*/=	ECHO;
(It's a bit more complex than ECHO, actually), and I get the error message.
Can anyone shed light on how right contexts are treated?
I get an error even if there is only one right context, as in the example.
-- 
Bill Silvert
Marine Ecology Lab.
Dartmouth, NS
dalcs!silvert
dalcs!biomel!bill