McLain,

I assume the issue you are running into is that after a certain point you can't add any more rows or columns without having the header values getting concatenated together in the first row or column?  By default, you can have 6 levels of rows or columns.  You can increase that to 16 (from the Analysis menu select "Table Layout" --> "Advanced".  But that won't get you to 45.

You could have 45 columns of measure values in a viz, but I don't see that after looking at your data.

One possibility is that if the 45 columns of data are your raw data source you can get that from a dashboard by selecting "View Data" and then look at the underlying raw data.

Beyond that...

...I'm sure you have a reason for wanting 45 columns in a detail table, but you're asking Tableau to do something it isn't designed to do: give you a bunch of raw data as a visualization.  Tableau is designed first and foremost to allow you to visualize data in ways that help you understand large amounts in an intuitive way.  A table with 45 columns of text doesn't fit that paradigm.

Having said that, there may be a way to meet your requirement.  But it may require you to do one or more of the following:

1. change your paradigm

2. refine your requirements

3. do something outside the box

If you can give some specifics of what you want to do and why you want to do it, it would probably open up a great discussion.

There's an idea here for a horizontal scroll bar: http://community.tableau.com/ideas/1136 I often have tables which would benefit from it