Thank you for feedback! I made the website with flex for two main reasons: efficiency (it took me 5 days to make the website) and the flex capabilities to play audio content (to play my audio records which is an important feature of my website). I used also flex because it is far to be a dead language as it is now an open source framework supported by Apache (Flex Apache).
I might add an HTML5 gallery when lightroom will be able to export HTML5 or redo the whole site in HTML5 once a great and simple HTML5 IDE with proper libraries will be on the market... or I could start learning PHP or java. But frankly, I prefer to shoot pictures during my free time than learning hardcore HTML5/java/PHP programming. Remember, I'm not a web developer. Regarding the security, I agree with you flash is not a great option but neither php, perl, asp or anything else (especially when poorly implemented). Anyway, my flash module is not linked to any database and there is no user input, this reduce the option of injecting code.... we will see how it goes before rewriting all the website in another script language.