Build FM DITABook from DITA Map file - xref and general questions

Hello,

I'm using Frame 8.0p277 on Windows XP Pro. I have some questions about the "Build FM DITABook from DITA Map file" function.

1) When using the "Build FM DITABook from DITA Map file", I'm noticing an issue with cross references (fm-xref). If I update/generate the book, an XML Read Report Log appears for each fm-xref target xml file. I've substituted the file/path names below to save space:

"Error at file C:\DITA\project_topics\sample.xml, line 9, char 3
Message: Could not open DTD file: C:\DITA\project_topics\ditabase.dtd
Parse error at line 9, char 1: Error in processing external entity reference
Parsing aborted"

Anyone have thoughts on why this might be happening? Shouldn't the fm-xref items live through the map-to-book process, and point at the appropriate areas in the FM files now?

2) Others have mentioned the directory structure affects the success/failure of using the map-to-book process. Are there any guidelines or best practices for setting up the directory structure?

Any help is greatly appreciated.

Thanks