Unrecognized option from ffmpeg converting to html 5 video on upload

I am gradually getting the hang of video conversion with ffmpeg but am stuck. I am on shared hosting. I can convert with simple code like -

ffmpeg -i out.avi -acodec copy -vcodec copy output.mp4

I need to convert to html5 video formats but whenever i use code like this, I always get the same type of error 'Unrecognized option c:v' or 'Unrecognized option b'. Is my version of ffmpeg too old? Please help.

exec("/usr/bin/ffmpeg -i input -c:v libx264 -preset slow -crf 18 -vf yadif -strict -2 output.mp4");



    array(31) { [0]=> string(67) "FFmpeg version 0.6.5, Copyright (c) 2000-2010 the FFmpeg developers"
 [1]=> string(74) " built on Jan 29 2012 23:55:02 with gcc 4.1.2 20080704 (Red Hat 4.1.2-51)" 
 [2]=> string(649) " configuration: --prefix=/usr --libdir=/usr/lib64 --shlibdir=/usr/lib64 
 --mandir=/usr/share/man --incdir=/usr/include --disable-avisynth --extra-cflags='-O2 -g -pipe 
 -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector --param=ssp-buffer-size=4 -m64 
 -mtune=generic -fPIC' --enable-avfilter --enable-avfilter-lavf --enable-libdirac --enable-libfaac 
 --enable-libfaad --enable-libfaadbin --enable-libgsm --enable-libmp3lame --enable-libopencore-amrnb 
 --enable-libopencore-amrwb --enable-libx264 --enable-gpl --enable-nonfree --enable-postproc 
 --enable-pthreads --enable-shared --enable-swscale --enable-vdpau --enable-version3 --enable-x11grab" 
 [3]=> string(35) " libavutil 50.15. 1 / 50.15. 1" [4]=> string(35) " libavcodec 52.72. 2 / 52.72. 2" 
 [5]=> string(35) " libavformat 52.64. 2 / 52.64. 2" [6]=> string(35) " libavdevice 52. 2. 0 / 52. 2. 0" 
 [7]=> string(35) " libavfilter 1.19. 0 / 1.19. 0" [8]=> string(35) " libswscale 0.11. 0 / 0.11. 0" 
 [9]=> string(35) " libpostproc 51. 2. 0 / 51. 2. 0" [10]=> string(72) "[flv @ 0xb278b0]Estimating 
 duration from bitrate, this may be inaccurate" [11]=> string(0) "" [12]=> string(99) "Seems stream 0 
 codec frame rate differs from container frame rate: 1000.00 (1000/1) -> 25.00 (25/1)" [13]=> string(42) 
 "Input #0, flv, from 'destinationfile.flv':" [14]=> string(11) " Metadata:" [15]=> string(23) " duration : 
 6" [16]=> string(25) " width : 320" [17]=> string(25) " height : 240" [18]=> string(25) " videodatarate : 
 195" [19]=> string(24) " framerate : 25" [20]=> string(23) " videocodecid : 2" [21]=> string(24) " 
 audiodatarate : 31" [22]=> string(27) " audiosamplerate : 22050" [23]=> string(24) " audiosamplesize : 
 16" [24]=> string(27) " stereo : false" [25]=> string(23) " audiocodecid : 2" [26]=> string(28) " 
 filesize : 352720" [27]=> string(59) " Duration: 00:00:05.64, start: 0.000000, bitrate: 232 kb/s" 
 [28]=> string(79) " Stream #0.0: Video: flv, yuv420p, 320x240, 200 kb/s, 25 tbr, 1k tbn, 1k tbc" 
 [29]=> string(63) " Stream #0.1: Audio: mp3, 22050 Hz, 1 channels, s16, 32 kb/s" [30]=> string(25) 
 "Unrecognized option 'c:v'" }