problem after reimaging 10.5 instalation

[modman860]

originally I had a 30gb partition intended for time machine, and the rest was for the boot volume. well after doing something stupid it showed a blinking _ at the top left of the screen, so I reimaged the laptop using acronis. Everything works fine, but I want to get back the missing hardrive space. I tried using a resize command in the terminal to just make the partition smaller so I could have another 20gb partition to use for time machine, but it failed each time I tried it. Any safe way to format the unused hardisk space? I'm willing to try anything since I can just reimage again, but would prefer it to work first try. resizing my 100gb partition is a last ditch option because I'd like to use all my hardisk space. I'll try to find the resize command I tried, but really would rather just partition the extra 30gb thats missing. under disk utility it shows my hardisk as being 149.1GB, but it has only one partition and that's 97.8GB. Please help since this is really bugging me and it's hard to find a solution. Thanks!

 

 

edit: here is the command I tried:

sudo diskutil resizeVolume disk0s1 77G HFS+ backup 20G

 

edit2: after trying this other command I found

sudo diskutil resizeVolume disk0s3 limits

 

I get the error

Resizing encountered error on disk disk0s1 T60P: Could not modify partition map (-9986)

 

maybe this is an osx86 only issue? or some kind of driver issue?