If AndGuard said that you did not have SU permissions and you believe this to be incorrect:
1) Enter Terminal Emulator and type "su" (This will check to see if you have SU Permissions, If it fails then your device is most likely NOT rooted) If that works...
2) Still in Terminal Emulator (with SU permissions, indicated by the # instead of the $) type "busybox mount -o rw,remount /system" (This will use busybox to remount your /system as Readable/Writeable... if this does not work, than you don't have access to write to the necessary filesystem or you don't have busybox and AndGuard will not work) If that works (indicated by an error message NOT being given) then...
3) Type "df" and look for /system in the output.... Does /system have 0K available? (This would indicate that /system is full, and therefore, the hosts blocklist cannot be written to it) If /system is NOT full...please let me know what model phone you have and what Rom you are running so that furthur investigation can be made.
Please email me back with any errors... and don't forget to include your Device Model and Rom!
If steps 1-3 work without error, then it is highly likely that the newest version of AndGuard (1.3.5 or later) has fixed your issue.
I will be compiling a list of Phones and Roms that AndGuard does and currently does not work on.... I will place this list on my blog in the upcoming days to avoid furthur unncessary dissatisfaction.