what rom did you install? where did you download it from?
and that tutorial you followed is pretty outdated.
did you use the rom manager app to install or did you manually boot into recovery?
1) i would redownload the rom. (check md5- see below)
2) manually go into recovery
3) wipe data
4) wipe cache
5) go to advanced, wipe dalvik cache
6) repeat steps 3-5
7) [optional] go to advanced, wipe system
8) install rom from zip
9) reboot
first boot will take a while (5-10 mins)
md5 sums (long string of characters) should be listed wherever you download the rom from, you can use an app like "mand5" to generate a sum and compare with what the dev lists. This guarantees file integrity.
edit: i see you flashed synergy, you can also check over at the xda forums and see if anyone else is having similar issues.
http://forum.xda-developers.com/showthread.php?t=1106799