64-bit instability

When building Thred with 64-bit support, certain actions cause a crash. Such things are building any stitches from a form, for instance.

This is caused by certain functions that require a passed pointer length being hardcoded to 4 instead of using sizeof(). Unfortunately, it looks like more than one function is affected, and at the state the code is in, it is very difficult to tell what exactly needs to be changed.

Note: These bug reports are more or less for informational/to-do purposes, I will be working on these myself at some point (unless someone else wants to take a look, too).