Iphone 4 app issue

Hello everyone, I'm hoping someone out there in the ether may be able to help with my small but frustrating problem.

I bought an new iphone 4 recently and have to say it is a thing of beauty...most of the time! I have created several ringtones of my own, creating m4a files in Audacity and have wanted to add them to my phone. The first time I tried, I downloaded and used a free app called Ringtone maker, as recommended on Apple's website. I successfully navigated my way through online youtube instructions and managed to get 3 of the 4 I want to use. Then things ground to a halt. I converted the 4th ringtone to an m4a file and added it to my itunes library. When I then tried to use the app to transfer it over to the phone, the app would not work and just left me with a white page and nowhere to navigate to. I deleted the app 3 times and reinstalled it but to no avail. I then tried another app called Ringtone converter app for iphone. Once loaded it did the same thing and just opened a white page and noting else. What could be going wrong? Any help here would be gratefully received