Have you checked online document about TalendHelpCenter:Compatible Platforms? Could you please try to use jdk 1.7 instead of jdk 1.8 to see if it is working?
question 3 : but for 8.1 PRO, is it the same ?
question 4 : which JDK 7 : 32 or 64 bits ?
question 5 : should the JRE 1.7 be sufficient ?
question 6 : should I install also the JDK ?