Missing text in RoboHelp 7 when previewing/generating Frame files

This is a new issue for me. Until last week, it seemed to work fine. Now, though, whenever I import by reference my frame files I have noticed that, while they look fine in the Design view, when I click Preview it has missing text in parts. In one file, which was all text (no graphics), it was completely in Preview. Then, when I generated the help, that topic was still blank.

This doesn't always happen, though. Sometimes a topic is fine up to a point, then, all the text is gone, leaving only the screenshots. It generates that way also. On the other hand, some files come out fine, with no missing text. (This is only apparent in the Preview and generated help.)

I'm using TCS 1, that has RoboHelp 7, and I generate to WebHelp. I've applied an update that makes it 7.01.001.  I've also applied the "missing space" fix that Peter Grainge suggested (it worked ).

Like I said, TCS worked fine up to last week, then I started seeing these missing chunks of text. I tried creating a new RH project and starting all over, importing only one small file that had all text and no screenshots/graphics. Both the preview and generated help came out blank, although I could see it plainly in the Design view before generating.

Has anyone else had this issue, or know what it might be?