The runnable files in linux versions are "Pixatool" the ones with 54-59kb. on 32/64bits.
BTW, i dropped linux support time ago due problems like this. Some people run without problems and others can't extract the files or comes with errors, thats why i set the app only Windows/Mac and set in the first line of description:
"** Test DEMO and read the Limitations List before buy **"
Some causes the linux version not work can be like in OSX, that depending in which program you use to extract the zip the tool will run or not. Are you using the .zip program or the own linux extractor for zips? In OSX the tool only will work if you extract the zip using the MAC one. No idea why, but if you use the zip programafter unzip it says the tool is damaged and can't be run.