I had a similar error about the CHECKHOST not finded. But smsconGUI open well after charging a default conf.
After that I have manually edited the file "smscon_conf" as describe in the wiki and have to type the exact patern found in the wiki after this using smsconGUI work perfectly

note : on a first time I tried with 'www.bla.com' but style have the error until I wrote 'www.bla.com/filetocheck'.
Thanks for this very nice app. And thanks for the wiki, the work around, and the error message easily understandable for a standard user.