Please follow these specific steps and this should repair your issue or another paid way must assist you http://www.dbx.openfiletool.com/
DBX Open File Tool
Step 1: Save your existing e-mail
Launch Outlook Express.
Create a new folder under Local Folder:
Right-click Local Folder (in the left bar)
Select New Folder
Type the name of the new folder (e.g. Saved E-Mails)
Select all your messages and move them into the new folder (e.g. Saved E-Mails).
Quit Outlook Express.
Once this has been done, we need to make sure we can have access to the inbox.dbx file. So now follow these steps.
Step 2: Show hidden files
Right-click the Start button and select Explore to open Windows Explorer or click Start and select My Computer.
Click the Tools menu and select Folder Options.
Click the View tab.
Select Show all hidden files and folders.
Next we are going to find the file so we can delete it. Outlook express will later recreate it.
Step 3: Search for ".dbx" files
1. Click Start and select Search.
2. Click All files and folders on the right.
3. Click Advanced options, then click More advanced options.
4. Make sure that Search hidden files and folders is selected.
5.In the box labelled All or part of the document name, type *.dbx.
Now once you finsih the search, the file inbox.dbx should come up in your search results. select the file and press delete.
Once you have done this, you can go back into Outlook Express and it should have fixed the issue.