Cryptic Error Message

I am new to LiveCycle Designer, having acquired it when I purchased Acrobat 9 Pro Extended.
 
I started to make a form using the sample Job application form template that I found in LCDesigner as a starting point. I saved it under a new name of Volunteer Application.PDF and then started modifying it to suit my needs. Everything went well for the first couple of hours or so. I managed to get the form nearly to the point I was striving for. But then after I changed a number of objects, including the Tab order for most of the objects in the form, I got the following message
 
"Failed to Save The File. Additional information can be found in the Log Tab of the Report Palette."
 
It took me nearly an hour to figure out how to see the Report Palette (I quickly and easily figured out how to select it to be displayed from the Window menu but was unable to actually see it until I stumbled on it finally after about an hour).
 
So the message in the Log tab was about a field called CompanyLogo, which was part of the original template I copied but had never touched. So I played with it for a while and finally just embedded a jpg file as my companylogo. But now I still get the same error message.
 
XFAImageService: Image cannot be resolved for node: CompanyLogo.
Hint: ImageStore loadEmbedded method failed. Key was [form1[0].#subform[0].Header[0].CompanyLogo[0]].
Error importing image. Unsupported image format.
XFAImageService: Image cannot be resolved for node: CompanyLogo.
Generating PDF Document...
Unable to open or create file C:\Users\Default1\Documents\@Songaia\Biogaians\& Volunteers\Volunteer Application.pdf
Permission denied
 
I don't understand why it can't resolve the image now nor why it couldn't before I changed it either. I am quite lost and don't know where to turn.