I have a dotnetnuke SQL database file (an MDF) that has grown from 200 mb, to 400 mb and now to 1.5 gb in size in a matter of a week.  The file size for my other installations have remained constant.  There is definitely NOT that much data being added.  Can someone help me out?  There is no shrinking or anything that can be done to reduce.  It shows that there is only like 120mb free space in the SQL file.

Oh yea... I am using 3.2.2

It is definitely not the LDF file, I know the difference.  Here is where I am on this issue:

• The MDF file was in fact 100 MB when all this started.  It grew to over 2 GB in size without explanation inside a week or so.
• Last night I discovered that 800mb of data in the sitelog and error log tables dating back to 2005.  Mysteriously, this same data was also in the 100 MB MDF file.
• Because of the size of these tables, the scheduler could not maintenance them and kept timing out.  The sitelog had 100,000+ entries; the error table had 35,000 entries.  I manually deleted the data rows and now my database is back under 400-600 MB. 
• I am still hunting for hidden data.  This is essentially the same file (short of adding a few pages) that I began with a few weeks ago. 
• Question: Why did these two tables suddenly impact the size of my MDF?