cacheEntry locked

[Zeke]

I'm trying to read in .ace files from one database to a new DB with some 
different model statements. I've encounter an error message:
"Sorry, cacheEntry CAT 91964185 is already locked" then clicking 
CONTINUE I get:
ERROR: parse error near line 28 in No object ://Object CAT 91964185 is 
locked - free before continuing.

CAT 91964185 is the main class designation of the data object I'm trying 
to read in. The designation does not appear in the data file before the 
trouble spot.

Can someone please tell me what this error means?

Thank you.