Convert LoadRunner 11 scripts to loadrunner 12

Hello,

I've been looking for help on this topic all over the internet. For an application I test, I can´t record on my 64 bit computer, so I use a virtual machine with LoadRunner 11. Then I open the script with LoadRunner 12.01. The problem is that sometimes LoadRunner 12 says that it can´t load the script because it is empty. Other times I fixed thi by ziping the script, or saving it agai, but now y have an script dat doesent upgrade. Any help regarding this problem would be great.

Thank you in advanvce,