Build a Self-Destructing Message iPhone App Error

Hello Ben, I am 15 minutes into the video titled "Upload the File and Message" and I ran into this error. despite the fact that build was successfully and xCode showed no yellow or red warnings.. The error message below appears when I attempt to select an image with the simulator and test sending it to my list of friend /users...any idea what I failed to do correctly? Here is the error message: 2013-08-26 16:35:03.311 opicnion[4322:12b03] current user: soj1 2013-08-26 16:35:06.182 opicnion[4322:17603] ADDRESPONSE - ADDING TO MEMORY ONLY: https://api.parse.com/2/find 2013-08-26 16:35:11.135 opicnion[4322:12b03] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Application tried to present modally an active controller <CameraViewController: 0x7cc93a0>.' *** First throw call stack: (0x1fbd012 0x1d30e7e 0xf87111 0xf88167 0x6f44 0xf81103 0xf8142b 0xf94052 0xf81103 0xf8142b 0xf9d3fd 0xf81103 0xf8142b 0xf8ef80 0x118b223 0xf89401 0xf888bd 0xf888bd 0xf895cb 0x7cc9 0x10a0e3e 0x1037dd11 0x10393546 0x104045e2 0x116885a 0x116799b 0x11690df 0x116bd2d 0x116bcac 0x1163a28 0xed0972 0xed0e53 0xeaed4a 0xea0698 0x2a6edf9 0x2a6ead0 0x1f32bf5 0x1f32962 0x1f63bb6 0x1f62f44 0x1f62e1b 0x2a6d7e3 0x2a6d668 0xe9dffc 0x2f7d 0x2ea5) libc++abi.dylib: terminate called throwing an exception

Hope to hear from you soon. Thanks.