Interested in Language
Could you shed some light on this?
I was hoping at seeing you again.
I was hoping to see you again.
What's the difference?
Yes, the second one is correct.
Here is some help. Certain verbs always go with gerunds (the -ing words) and certain verbs go with infinitives (to verb). I think just a few can use either.
Here is a way to check which one applies.
Gerund or Infinitive? An Interactive Quiz
These come to native speakers naturally, but ESL learners need to check out the lists of which verbs go with one form or the other. After you do exercises a few times, hopefully you will develop a sense of which sounds correct.
Do a search using "verbs gerunds infinitives" for more information and lists and examples.