I am trying to convert Quote to an invoice but nothing happens. I just checked to see if I could create an invoice and have the same issue. Bit of a headache as I need to send invoices 
Thanks Mark
Debian 7
PHP Version 5.6.23-0+deb8u1
Version 1.4.8
Error log
ERROR - 2016-09-20 14:14:51 --> Could not find the language line "generate_invoice_number_for_draft"
ERROR - 2016-09-20 14:14:51 --> Could not find the language line "pdf_settings"
ERROR - 2016-09-20 14:14:51 --> Could not find the language line "email_settings"
ERROR - 2016-09-20 14:14:51 --> Could not find the language line "other_settings"
ERROR - 2016-09-20 14:14:51 --> Could not find the language line "general_settings"
ERROR - 2016-09-20 14:14:51 --> Could not find the language line "generate_quote_number_for_draft"
Console output
SyntaxError: JSON.parse: unexpected end of data at line 1 column 1 of the JSON datajquery-1.12.3.min.js line 2 > eval()jquery-... > eval (line 17)data = ""n.Callbacks/i()jquery-....min.js (line 2)n.Callbacks/j.fireWith()jquery-....min.js (line 2)a = Object { url="http://pay.worxforu.com/...s/ajax/quote_to_invoice", type="POST", isLocal=false, more...}c = [Object { url="http://pay.worxforu.com/...s/ajax/quote_to_invoice", type="POST", isLocal=false, more...}, ["", "success", Object { readyState=4, status=200, statusText="OK", more...}]]y()jquery-....min.js (line 4)b = 200c = "OK"d = Object { text=""}e = "Date: Tue, 20 Sep 2016 1...t/html; charset=UTF-8\r\n".send/c()jquery-....min.js (line 4)a = readystatechange d = undefined
var response = JSON.parse(data);