Hi Xavier,
Sorry to hear you have a problem. Looking at the screenshot I don't really see anything that could cause this. Is this the only document/page that throws this error? Is Ivy working for other documents that you have? Just trying to see if there is anything caused by your environment configuration or local settings.
If Ivy works for other documents then it must be something with this specific PDF. Is there any way you could share this document with us so we could investigate further (assuming it's not confidential)?
If this is possible please email it to support@ivytools.com
Thank you!
Andrew