This is a bug in Mac OS X 10.4.x (all versions as of June, 2006)
Specifically, if an input method is active (any input method, including Apple's own that ship with OS X), you will be unable to type into most of the editable text fields (number of copies, page range, etc.) in the application-modal version of the Print dialog (not attached to the document's window). See Figure 1 below.
Figure 1. Application-modal Print dialog
This is not a problem in the document-modal (sheet) version of the Print dialog (attached to the document's window). See Figure 2 below.
Figure 2. Document-modal Print dialog (sheet)
To clarify the difference, the document-modal versions are "attached" to the actual document you are printing, while the application-modal versions appear in front of all document windows in the application.
Updated Nov 29, 2006 - New Advice and a "Better Way"
The only work-around is to choose a keyboard (flag) icon from the input menu in order to input text. Enter the number of copies (or page range, etc.), then choose Spell Catcher again from the input menu once you're done. The easiest way to do this is via the Select the previous input source Input menu keyboard shortcut. We were recommending that you use the default command-space and command-option-space keyboard shortcuts for the input menu. Due to recent discoveries (see below), we're recommending different, very specific keyboard shortcuts instead.
What we've just discovered is that this bug is even worse than we first thought. So nasty, in fact, that you can't even use the default command-space and command-option-space shortcuts to change the input source when you really need to - when in one of these "unchangeable" editable text fields! Sure, you can always select your keyboard from the input menu with the mouse, but that's pretty sub-optimal. So, if you forgot to type command-space before choosing the Print command, you're (somewhat) out of luck - take your hands off the keyboard and use the mouse? No thanks.
The Mysteriously-Yet-Optimal Input Menu Keyboard Shortcuts
The text input handling in these problematic Print dialog editable text fields is so bad, you can't even switch input sources with command-space or command-option-space (seriously - stealing the default input menu keyboard shortcuts such that they don't work?). Luckily, it's so bad that the bugs seem to have bugs. Anyway, there seems to be one set of magical keyboard shortcuts that will work, and the secret involves the tab character (but not the tab key). Tabbing is handled is some funky kind of way, making it possible to use keyboard shortcuts based on the tab character to switch input sources. But you can't use tab key - you have to use the equivalent control sequence - control-i == ASCII 9 == a tab character.
So if you choose keyboard shortcuts for the input menu that include control-i and a non-printing modifier (you can't use control-i alone - it generates a tab character), things work the way they should, even in these evil Print dialog fields.
One Minor Gotcha
Just one little thing to consider, at least if you haven't changed the keyboard shortcut for Spell Catcher's Interactive Checking command in the input menu. By default, it's command-control-i. So we steer clear to avoid a conflict with the "control-i" shortcuts we choose for the input menu.
If you run into this problem on a regular basis, and want the quickest and easiest way to work around it, we recommend changing your input menu keyboard shortcuts to the following:
Select the previous input source: control-shift-i
Select the next input source in the Input menu: control-option-i
There are a few others that will work, but not many. Your mileage may vary depending on your preferred keyboard layout as well.
Yuck. But it seems to work. Still. Yuck again.
Ask Apple to Fix This
Once again, this is not a bug in Spell Catcher. If the above fact related to the default (command-space, command-option-space) input menu keyboard shortcuts not working doesn't convince you, try changing the number of copies with (say) Apple's Korean (Hangul) input method active. The result - a total mess.
Again, we cannot fix or work-around this problem because it is a bug in Mac OS X (Tiger), and appears with almost all input methods. Tell Apple you'd like them to fix this if it's causing you grief.