are the instructions to use old points in the install file?

The installation instructions say to edit the following templates:

MEMBERINFO
postbit and/or postbit_legacy
navbar template

Yes, none of which should be a problem for online.php or index.php outside of the navbar, and if you did the edits badly it would error on all pages.

On a default installation:
[sql]UPDATE user SET uttpoints=0;[/sql]

Zachery is right. Even if the errors started coming up after you installed this, it doesn't appear to be anything related to it, and if it did, then it is user error. I have not seen one report of that in the 2,237 posts in the thread, nor in the numerous threads at GeekyDesigns.com, since this hack was released 8 months ago.

how do I keep lesanes cash amount for everyone upon install?

You have two options. The first is setting the Points Field (in uCash Options) to "storep". The seconds, which I'd recommend, is running this query.

[sql]UPDATE user SET uttpoints=uttpoints+storep;[/sql]

If everything goes well and you want to get rid of the redundant column in the user table, you can run this query afterwards.

[sql]ALTER TABLE user DROP storep;[/sql]

I just installed this and I'm having a few problems with it, first the 'Store' link is not appearing on the navbar and I have edited the navbar template. And in my admincp in the Action Manager when I try to save the values I get an error saying "Could not find phrase 'uttstore_saved_values_successfully'." Also I was wondering can anyone tell me how to change the welcome text on the store?

how would I add the feature when someone donates that the reciever gets a PM?

Just curious, was thinking about adding the vb arcade. I know you can "buy" a pass in Ushop. But can you set it up so that people can "win" money in the vb arcade games, and have that money reflect in their Ushop ucash amount?? I searched this thread and found nothing about this backwards interaction.