diff --git a/src/daqd/CMakeLists.txt b/src/daqd/CMakeLists.txt
index 11639cc34778c0f425acc11f4a79838065a4c4bf..9d72ab6f54a683267076342dd8fbf428fe19dde9 100644
--- a/src/daqd/CMakeLists.txt
+++ b/src/daqd/CMakeLists.txt
@@ -1,6 +1,13 @@
 FIND_PROGRAM(UNAME_PROG uname)
 FIND_PROGRAM(DATE_PROG date)
 
+FIND_PATH(FLEX_LEXER_PATH FlexLexer.h
+		HINTS /usr/include)
+message("Flex lexer path = '${FLEX_LEXER_PATH}'")
+if (NOT FLEX_LEXER_PATH)
+	message(FATAL_ERROR "FlexLexer.h is not found.  On debian this is in the libfl-dev package")
+endif (NOT FLEX_LEXER_PATH)
+
 INCLUDE(Cpp11)
 INCLUDE(CheckCXXSourceCompiles)