Can reproduce it in OOo310m9 on WinXP and Fedora9

How to reproduce it
1 Create a new Writer file
2 Insert a table with several rows and columns
3 Set the cursor under the inserted table and ENTER, then input some characters
4 CTRL + F, input '^$' without single quotation marks in the "Search for" text,
  input nothing in the "Replace with" text, click "More options", check 
  "Regular Expressions", then click "Replace All" button

Result
An dialog to turn off the "undo" function is opened, click "Yes" or "Cancle" 
can make OOo freezing, if click "No", dialog shows "Search key replaced 60000 
times"

Expectation
Replace the black paragraph successfully