Hey Sam, good to see you're back around!!
I've never encountered your error message, seems like "LoadTgaTexture.....couldnotbelocated......" is a problem with not finding the "Load Screen" image? Whatever it is, a reinstall might fix it.
Since you're going to v1.5, I'd not try to run the game before getting it installed. As I remember, the first several versions required you to keep the original disk in the CD to verify authenticity, version 1.3 or v1.4 did away with that requirement.
I've got my original v1.0 disk too, but bought the "Gold Edition" for about 8 dollars a couple of years ago. I quit messing with the updating. INetVideo is still selling the DVD for 14.99 plus shipping.....found
HERE.
Since you've got a 64 bit OS and 4gb of ram, put all 4 gigs to use with an app like
Large Address Aware. It will make this old game run much better!
Best Regards