Unfortunately the most important logs, converter-worker, are missing. You can find them in %ALLUSERSPROFILE%\vmware\VMware vCenter Converter Standalone\ folder, check for .dmp files too.
Also you should check your computer for viruses because the last message in the log is
2015-04-24T03:38:22.650-04:00 [03224 warning 'Default'] Error: 'Error when verify signature is: -2146762486 Error: 2148204810' checking for file 'C:\Program Files (x86)\VMware\VMware vCenter Converter Standalone\zip.exe' signature
which is indication for problems, mostly if you can see the proper digital signature from file properties.