what format is it in on the camera? is it AVI, or some Sony proprietary format, or what?
what model of camera is it?
are you converting it right off the camera? if so, try taking the file onto an internal hard drive and then converting it.
to where are you outputting it? how much free space is on that hard drive? you'll probably want 2 or 3 times the amount of space free as what the file will output to
what operating system are you using? Is it windows XP or what? if it's some flavor of windows, make sure to use the Disk Cleanup to ensure that you have no temporary files on the system prior to doing the conversion, as windows doesn't handle temp files very well. on XP, you can go to Start->Run and type "cleanmgr.exe" and then click OK to start Disk Cleanup.
again, if it's windows, try converting with no other programs running in the background, since it is possible that they are causing a conflict. use the instructions in the following document to correctly accomplish this:
http://support.microsoft.com/kb/310353
if your camera can connect with FireWire, try capturing the video file directly off the camera using a program like
DVIO, which will make an AVI. then, if you want it on a DVD, some burning programs can use the AVI file to do this. otherwise, first use a program like
bbMPEG to get into MPEG2 format which is what DVDs use.
HTH