Custom Thumbnail Size Issue

Hello Again,
Sorry to bother but ran into another issue. I started this THREAD before and was able to add in the custom thumbnail size needed and plugin however now the images are no longer "clickable" when the post goes live. Instead of thumbnails they seem to be adjusted to that size. Further more if we looks closely at the code when inserting a photo much of it is missing.

Previous photo upload:

<center><a href="http://instigatorgaming.com/wp-content/uploads/2010/08/10.0.9.11-image119_bmp_jpgcopy.jpg"><img src="http://instigatorgaming.com/wp-content/uploads/2010/08/10.0.9.11-image119_bmp_jpgcopy-300x168.jpg" alt="" title="10.0.9.11-image119_bmp_jpgcopy" width="300" height="168" class="alignnone size-medium wp-image-1493" /></a><a href="http://instigatorgaming.com/wp-content/uploads/2010/08/10.0.9.11-image125_bmp_jpgcopy.jpg"><img src="http://instigatorgaming.com/wp-content/uploads/2010/08/10.0.9.11-image125_bmp_jpgcopy-300x168.jpg" alt="" title="10.0.9.11-image125_bmp_jpgcopy" width="300" height="168" class="alignnone size-medium wp-image-1494" /></a></center>

This is what it looks like now when I attempt:

<img src="http://instigatorgaming.com/wp-content/uploads/2010/08/HD577XZMF3-2-600x456.jpg" alt="" title="HD577XZMF3-2" width="600" height="456" class="aligncenter size-large wp-image-1497" />

Thanks in advance.