If Lightning Tools creates a new version on the Lightning Tools Data Viewer Web Part, there is no need to remove the web part any where or delete the old wsp file, you can simply upgrade it by following these steps:

1. Download the new version of the LT DVWP

2. Unzip the downloaded file.

3. Open a command prompt by choosing Start, Run, and typing CMD

4. Navigate to the 12\bin directory

5. Type STSADM.exe -o upgradesolution -filename ltdataviewerwebpart.wsp -name ltdataviewerwebpart.wsp -allowcaspolicies -immediate

6. Type STSADM.exe -o ExecAdmSvcJobs.

7. Test the refreshed Web Part.