Avoid + gerund
There are certain verbs which are always followed by the present participle form of a verb (or gerund) and not by an infinitive.
Incorrect: You should avoid to make mistakes.
Correct : You should avoid making mistakes.
Incorrect : I could not help ( = could not avoid) to laugh.
Correct : I could not help laughing.
Note: But when ‘help’ means ‘assist’, it may be followed by a bare infinitive or to-infinitive.
For example:
I helped him write the application.
Or
I helped him to write the application.