Solr 4.10.4: Could not create instance of 'SolrInputDocument'

[Paul Revere]

Our web site is created using PaperThin's CommonSpot CMS in a ColdFusion 10 and 
Windows Server 2008 R2 environment, using Apache Solr 4.10.4 instead of CF 
Solr. We create collections through the CMS interface and they do appear in 
both the CMS and the Solr dashboard when created. However, when we try indexing 
our collections through the CMS interface, our CMS error logs show the entry 
'Could not create instance of 'SolrInputDocument'' for each member of the 
collection. This is not a fatal error, as the indexing appears to cycle through 
all members, but each member "errors out" with log entries for each member.  
I've Googled this error message without success. What might this error message 
indicate please??
Paul

Error: Could not create instance of 'SolrInputDocument'

[Paul Revere]

We are running PaperThin's CommonSpot CMS in a Cold Fusion 10 and MS SQL Server 
2008 R2 environment. We're using Apache Solr 4.10.4 vice Cold Fusion's Solr. We 
can create (and delete) collections through the CS CMS; they appear in (and 
disappear from) both the physical file structure as well as the Apache Solr 
dashboard. When we try indexing a collection through our CS CMS, it appears 
that each member is being indexed, however, each member "errors out" 
[Error.see logs] and indexing continues to the next member, only to error 
out again, etc., etc., etc. Eventually the entire collection "is indexed" in 
this fashion, and we received a message that the collection has been indexed 
and optimized. Our keyword search fails, returning 0 results.

Our log files show entries for each member indexed:

Error: Could not create instance of 'SolrInputDocument'.
~~
Exception: org.apache.solr.common.SolrInputDocument

We're obiously missing something, but this is our first time using Apache Solr 
and aren't sure where things may be broken.
Many thanks for any/all recommendations/guidance.

Thanks!

Paul R.