executing programs

[bigbuddy]

I have more problems with my phone. I notice when I'm using it sometimes like agile messenger my phone will turn its contrast all the way up and it will pop up with a notification error saying the location of the file and it being some what executed or execution error as if its trying to close while I'm using it and it cant and I noticed when I got to other programs or any other thing it cannot be found and the Icons in the programs files symbols change showing that the file or program isn't there. and then its like everythong disappeared I can't even click phonebook with out it not being shown. and sometimes I can't even go to the today's screen. can anyone help?