Before opening the report, fonts are showed ok, as this screenshot shows:

After the report is previewed, app fonts are changed to this (boldened):

The bolder fonts aren't the only problem, if I try to re-open the report, it is completely screwed.
This only happens on a specific report, the app uses many reports and I can see all ok but this one.
Could it be that the report uses a font not installed on my PC?.
One more thing, the report engine comes from a dll.
I hope someone can help me.
Regards,
Martín.