Strange problems with unit cards

[Monkwarrior]

I've just discovered some problems that are making me crazy.

First, I have a mercenary unit recruitable for all the factions in custom battles.
I have then one unique unit card in the merc folder, and the card is shown without problems in 18 factions, but it doesn't appear in romans_julii and carthage. Instead the card, I have a completely white card, even no the peasant or the background texture.

Something similar happens with several rebel units, from the thrace faction.
In campaign, when I spy rebel settlements with those units, the cards are shown without problems in the settlement pannel.
However, in a historical battle where the same units are used, they don't appear in the army selection pannel, but again the white cards (no peasant, no texture background).

Does anybody have a solution for this problem?

Edit: the problem is even more strange. When I minimize RTW and restore, then the unit cards are visible. When I change the screen and return to the problematic one, the problem is again present. Can it be a problem of video options?