Report Builder File Error 100

Today had an interesting problem, when opening Report Builder could
not see any reports to open. Restored report library from back up and
still could not see any reports. Made very simple report and tried to
save it to library then received message "file error 100". Referenced
answer book # 171.947MPS that suggested I create a simple report and
use "copy report" to open library that didn't work either. I ended up
restoring original file to a different location, renaming the library
and linking that to report builder. I'm wondering if any one else has
had a similar problem and if this is a symptom of a bigger problem of
something corrupting files?