Zero denominator in ratio multiply (17 :: 17)

Hi-

I'm using After Effects CS6 and suddenly have an issue with rendering.

1920x1080 size to MPEG4

When I set up the format from AVI to MPEG4, I can find the warning on the bottom.

Warning : Output file will be resized from 1920x1080 (1.00 PAR) to 176 x 120 (1.21 PAR) to meet format constraints.

Warning: Frame rate of output file will be adjusted from 30 to 15 fps to meet format constraints. Audio my not synchronize.

At first, I ignored and I got the renderings.

Then I tried few more times to get a better quality or something.

It showed up zero denominator in ratio multiply (17 :: 17) and I can't rendering anymore..

I don't know what the problem is and can't find the solution.

I tried rebut the computer.

Is this a computer problem? or I made up something wrong?

Please help me !~~

System

Processor: Intel Core i5-6600 CPU @ 3.30GHz

RAM: 8.00GB

System type : 64 bit