This is a rare, but known problem that somehow correlates with the use of midi or ethernet controllers. This should be fixed in the Pro Tools 5.1.1 update which should be shipping soon.
Here are the instructions for increasing the amount of tokens that Pro Tools
will create. This should fix the problems with the error messages saying
running out of 82 byte tokens or other sized tokens.

To specify additional tokens should be allocated, create a text file called
"TokenSizes.txt" and place it in the "DAE Folder" if on the Mac or the "Pro
Tools" folder if on the PC.
In this file you'll add up to 8 lines, each line of the format:

Size:CountXXX YYY:ZZZ

where XXX is a number between 1 and 8. YYY is a particular size of a token and
ZZZ is the additional # of tokens of size XXX to allocate.

Say for example you're running out of 8 and 82 byte tokens. To fix this, you'd
create a "TokenSizes.txt" file that contains the following 2 lines:

Size:Count1 8:500
Size:Count2 82:400

These 2 lines instruct DAE to allocate an additional 500 8 byte tokens and 400
82 byte tokens.
If you create a"TokenSizes.txt" file, a second file called
"TokenSizes.txt.ack.txt" will be auto-created by DAE to notify you whether DAE
correctly parsed the file or not.
Please contact tech support if you still have questions about doing this or have
problems once you have created this file.


This should be fixed in the Pro Tools 5.1.1 update which should be shipping soon.